14. Database Access |
Module Sql |
The SQL module is a unified interface between pike and all its supported databases. The parts of this module that is usuable for all normal uses is the Sql class and the sql_result class.
string people_in_group(string group) { Sql.Sql db = Sql.Sql("mysql://localhost/testdb"); return db->query("SELECT name FROM users WHERE " "group=%s", group)->name * ","; }
Val.Null Sql.NULL
Val.null
CLASS Sql.Null |
This class is used to implement the SQL NULL value.
There's typically only one object of this class: Sql.NULL , but some databases (eg Oracle) have multiple types of NULL, in which case they all inherit this class.
Val.Null , Val.null , Sql.NULL
string encode_json()
Defined for use with Standards.JSON.encode , so that it
formats NULL as null
.
CLASS Sql.mysqls |
Implements SQL-urls for mysqls://[user[:password]@][hostname][:port][/database]
Sets the connection to SSL-mode, and sets the default configuration
file to "/etc/my.cnf"
.
Ought to load a suitable default configuration file for Win32 too.
This connection method only exists if the Mysql-module has been compiled with SSL-support.
inherit Sql.mysql : mysql
CLASS Sql.sql_result |
Implements the generic result of the SQL-interface. Used for return results from SQL.sql->big_query().
mixed Sql.sql_result.master_res
The actual result.
int Sql.sql_result.index
This is the number of the current row. The actual semantics differs between different databases.
void Sql.sql_result(mixed res)
Create a new Sql.sql_result object
Result to use as base.
int num_rows()
Returns the number of rows in the result.
int num_fields()
Returns the number of fields in the result.
int eof()
Returns non-zero if there are no more rows.
array(mapping(string:mixed)) fetch_fields()
Return information about the available fields.
void seek(int skip)
Skip past a number of rows.
Number of rows to skip.
int|array(string|int|float) fetch_row()
Fetch the next row from the result.
Returns an array with one element per field in the same order as reported by fetch_fields() . See the Sql.Sql class documentation for more details on how different data types are represented.
string fetch_json_result()
Fetch remaining result as JSON-encoded data.
CLASS Sql.msql |
Implements the glue needed to access the Msql-module from the generic SQL module.
inherit Msql.msql : msql
CLASS Sql.Sql |
This class encapsulates a connection to an SQL server. It is a generic interface on top of the DB server specific implementations. That doesn't mean that there aren't plenty of server specific characteristics that still shine through, though.
This class also serves as an interface guideline for the DB server specific connection classes.
The query results are returned in different ways depending on the query functions used: The ..typed_query functions select typed mode, while the other query functions uses the older untyped mode.
In untyped mode, all values except SQL NULL are returned as strings in their display representation, and SQL NULL is returned as zero.
In typed mode, values are returned in pike native form where it works well. That means at least that SQL integer fields are returned as pike integers, floats as floats, SQL NULL as Val.null , and of course strings still as strings. The representation of other SQL types depend on the capabilities of the server specific backends. It's also possible that floats in some cases are represented in other ways if too much precision is lost in the conversion to pike floats.
For historical reasons, there may be server specific backends that operate differently from what is described here, e.g. some that return a bit of typed data in untyped mode.
Typed operation was not supported at all prior to Pike 7.8.363, and may not be supported for all databases.
object Sql.Sql.master_sql
Server specific connection object used for the actual SQL queries.
int(0..1) Sql.Sql.case_convert
Convert all field names in mappings to lower_case. Only relevant to databases which only implement big_query(), and use upper/mixed-case fieldnames (eg Oracle).
|
string quote(string s)
Quote a string s so that it can safely be put in a query.
All input that is used in SQL-querys should be quoted to prevent SQL injections.
Consider this harmfull code:
string my_input = "rob' OR name!='rob";
string my_query = "DELETE FROM tblUsers WHERE name='"+my_input+"'";
my_db->query(my_query);
This type of problems can be avoided by quoting my_input. my_input would then probably read something like rob\' OR name!=\'rob
Usually this is done - not by calling quote explicitly - but through using a sprintf like syntax
string my_input = "rob' OR name!='rob";
my_db->query("DELETE FROM tblUsers WHERE name=%s",my_input);
string encode_time(int t, int|void is_utc)
Converts a system time value to an appropriately formatted time spec for the database.
Time to encode.
If nonzero then time is taken as a "full" unix time spec (where the date part is ignored), otherwise it's converted as a seconds-since-midnight value.
int decode_time(string t, int|void want_utc)
Converts a database time spec to a system time value.
Time spec to decode.
Take the date part from this system time value. If zero, a seconds-since-midnight value is returned.
string encode_date(int t)
Converts a system time value to an appropriately formatted date-only spec for the database.
Time to encode.
int decode_date(string d)
Converts a database date-only spec to a system time value.
Date spec to decode.
string encode_datetime(int t)
Converts a system time value to an appropriately formatted date and time spec for the database.
Time to encode.
int decode_datetime(string datetime)
Converts a database date and time spec to a system time value.
Date and time spec to decode.
void Sql.Sql(string host)
void Sql.Sql(string host, string db)
void Sql.Sql(string host, mapping(string:int|string) options)
void Sql.Sql(string host, string db, string user)
void Sql.Sql(string host, string db, string user, string password)
void Sql.Sql(string host, string db, string user, string password, mapping(string:int|string) options)
void Sql.Sql(object host)
void Sql.Sql(object host, string db)
Create a new generic SQL object.
|
Select this database.
User name to access the database as.
Password to access the database.
Optional mapping of options. See the SQL-database documentation for the supported options. (eg Mysql.mysql()->create() ).
In versions of Pike prior to 7.2 it was possible to leave out the dbtype, but that has been deprecated, since it never worked well.
Support for options was added in Pike 7.3.
int is_open()
Returns true if the connection seems to be open.
This function only checks that there's an open connection, and that the other end hasn't closed it yet. No data is sent over the connection.
For a more reliable check of whether the connection is alive, please use ping() .
ping()
int ping()
Check whether the connection is alive.
Returns one of the following:
|
is_open()
void set_charset(string charset)
Changes the charset that the connection uses for queries and returned text strings.
The charset to use. The valid values and their meanings depends
on the database brand. However, the special value
"unicode"
(if supported) selects a mode where the query
and result strings are unencoded (and possibly wide) unicode
strings.
An error is thrown if the connection doesn't support the specified charset, or doesn't support charsets being set this way at all.
See the set_charset
functions for each database
connection type for further details about the effects on the
connection.
get_charset , Sql.mysql.set_charset
string get_charset()
Returns the (database dependent) name of the charset used for (at least) query strings. Returns zero if the connection doesn't support charsets this way (typically means that a call to set_charset will throw an error).
set_charset , Sql.mysql.get_charset
int|string error()
Return last error message.
void select_db(string db)
Select database to access.
string|object compile_query(string q)
Compiles the query (if possible). Otherwise returns it as is. The resulting object can be used multiple times to the query functions.
SQL-query to compile.
query , typed_query , big_query , big_typed_query , streaming_query , streaming_typed_query
protected ZeroWrapper Sql.Sql.zero
Instance of Zerowrapper used by handle_extraargs() .
array(string|mapping(string|int:mixed)) handle_extraargs(string query, array(mixed) extraargs)
Handle sprintf -based quoted arguments
The query as sent to one of the query functions.
The arguments following the query.
Returns an array with two elements:
|
array(mapping(string:string)) query(object|string q, mixed ... extraargs)
Sends an SQL query synchronously to the underlying SQL-server and returns the results in untyped mode.
Query to send to the SQL-server. This can either be a string with the query, or a previously compiled query (see compile_query() ).
This parameter, if specified, can be in two forms:
A mapping containing bindings of variables used in the query. A variable is identified by a colon (:) followed by a name or number. Each index in the mapping corresponds to one such variable, and the value for that index is substituted (quoted) into the query wherever the variable is used.
res = query("SELECT foo FROM bar WHERE gazonk=:baz",
([":baz":"value"]));
Binary values (BLOBs) may need to be placed in multisets.
Arguments as you would use in sprintf. They are automatically quoted.
res = query("select foo from bar where gazonk=%s","value");
Returns one of the following on success:
|
Throws an exception if the query fails.
typed_query , big_query , streaming_query
array(mapping(string:mixed)) typed_query(object|string q, mixed ... extraargs)
Sends an SQL query synchronously to the underlying SQL-server and returns the results in typed mode.
For the arguments, please see the query() function.
Returns one of the following on success:
|
Typed mode is not supported by all sql databases. If not supported, an error is thrown.
query , big_typed_query
int|object big_query(object|string q, mixed ... extraargs)
Sends an SQL query synchronously to the underlying SQL-server and returns the results in untyped mode.
For the arguments, please see the query() function.
The result is returned as an Sql.sql_result object in untyped
mode. This allows for having some more info about the result as
well as processing the result in a streaming fashion, although the
result itself wasn't obtained streamingly from the server. Returns
0
if the query didn't return any result (e.g. INSERT
or similar).
Despite the name, this function is not only useful for "big" queries. It typically has less overhead than query also for ones that return only a few rows.
query , streaming_query
int|object big_typed_query(object|string q, mixed ... extraargs)
Sends an SQL query synchronously to the underlying SQL-server and returns the results in typed mode.
For the arguments, please see the query() function.
The result is returned as an Sql.sql_result object in typed
mode. This allows for having some more info about the result as
well as processing the result in a streaming fashion, although the
result itself wasn't obtained streamingly from the server. Returns
0
if the query didn't return any result (e.g. INSERT
or similar).
Typed mode is not supported by all sql databases. If not supported, an error is thrown.
Despite the name, this function is not only useful for "big" queries. It typically has less overhead than typed_query also for ones that return only a few rows.
query , typed_query , big_query , streaming_query
int|object streaming_query(object|string q, mixed ... extraargs)
Sends an SQL query synchronously to the underlying SQL-server and returns the results streaming in untyped mode.
For the arguments, please see the query() function.
The result is returned as a streaming Sql.sql_result object in
untyped mode. This allows for having results larger than the
available memory, and returning some more info about the result.
Returns 0
if the query didn't return any result (e.g.
INSERT or similar). For the other arguments, they are the same as
for the query() function.
Streaming operation is not supported by all sql databases. If not supported, this function will fall back to calling big_query() .
big_query , streaming_typed_query
int|object streaming_typed_query(object|string q, mixed ... extraargs)
Sends an SQL query synchronously to the underlying SQL-server and returns the results streaming in typed mode.
For the arguments, please see the query() function.
The result is returned as a streaming Sql.sql_result object in
typed mode. This allows for having results larger than the
available memory, and returning some more info about the result.
Returns 0
if the query didn't return any result (e.g.
INSERT or similar).
Neither streaming operation nor typed results are supported by all sql databases. If not supported, this function will fall back to calling big_typed_query() .
streaming_query , big_typed_query
void create_db(string db)
Create a new database.
Name of database to create.
void drop_db(string db)
Drop database
Name of database to drop.
void shutdown()
Shutdown a database server.
void reload()
Reload the tables.
string server_info()
Return info about the current SQL-server.
string host_info()
Return info about the connection to the SQL-server.
array(string) list_dbs(string|void wild)
List available databases on this SQL-server.
Optional wildcard to match against.
array(string) list_tables(string|void wild)
List tables available in the current database.
Optional wildcard to match against.
array(mapping(string:mixed)) list_fields(string table, string|void wild)
List fields available in the specified table
Table to list the fields of.
Optional wildcard to match against.
CLASS Sql.Sql.ZeroWrapper |
Wrapper to handle zero.
zero
string _sprintf(int fmt, mapping(string:mixed) params)
Returns the following:
|
Otherwise it formats a 0
(zero).
CLASS Sql.mysql |
This class encapsulates a connection to a MySQL server, and implements the glue needed to access the Mysql module from the generic SQL module.
When query results are returned in typed mode, the MySQL data types are represented like this:
Returned as Val.null .
Returned as pike integers.
Returned as pike floats.
Returned as pike integers for fields that are declared to contain zero decimals, otherwise returned as Gmp.mpq objects.
Returned as strings in their display representation (see the MySQL manual).
Calendar objects are not used partly because they always represent a specific point or range in time, which these MySQL types do not.
Also returned as strings in the display representation.
The reason is that it's both more efficient and more robust (wrt time zone interpretations) to convert these to unix timestamps on the MySQL side rather than in the client glue. I.e. use the UNIX_TIMESTAMP function in the queries to retrieve them as unix timestamps on integer form.
All string types are returned as pike strings. The MySQL glue can handle charset conversions for text strings - see set_charset and set_unicode_decode_mode .
inherit Mysql.mysql : mysql
int(0..1) set_unicode_encode_mode(int enable)
Enables or disables unicode encode mode.
In this mode, if the server supports UTF-8 and the connection
charset is latin1
(the default) or unicode
then
big_query handles wide unicode queries. Enabled by default.
Unicode encode mode works as follows: Eight bit strings are sent
as latin1
and wide strings are sent using utf8
.
big_query sends SET character_set_client
statements as
necessary to update the charset on the server side. If the server
doesn't support that then it fails, but the wide string query
would fail anyway.
To make this transparent, string literals with introducers (e.g.
_binary 'foo'
) are excluded from the UTF-8 encoding. This
means that big_query needs to do some superficial parsing of
the query when it is a wide string.
|
Note that this mode doesn't affect the MySQL system variable
character_set_connection
, i.e. it will still be set to
latin1
by default which means server functions like
UPPER()
won't handle non-latin1
characters
correctly in all cases.
To fix that, do set_charset ("unicode")
. That will
allow unicode encode mode to work while utf8
is fully
enabled at the server side.
Tip: If you enable utf8
on the server side, you need to
send raw binary strings as _binary'...'
. Otherwise they
will get UTF-8 encoded by the server.
When unicode encode mode is enabled and the connection charset
is latin1
, the charset accepted by big_query is not
quite Unicode since latin1
is based on cp1252
.
The differences are in the range 0x80..0x9f
where
Unicode has control chars.
This small discrepancy is not present when the connection
charset is unicode
.
set_unicode_decode_mode , set_charset
int get_unicode_encode_mode()
Returns nonzero if unicode encode mode is enabled, zero otherwise.
set_unicode_encode_mode
void set_unicode_decode_mode(int enable)
Enable or disable unicode decode mode.
In this mode, if the server supports UTF-8 then non-binary text strings in results are automatically decoded to (possibly wide) unicode strings. Not enabled by default.
The statement "SET character_set_results = utf8
" is sent
to the server to enable the mode. When the mode is disabled,
"SET character_set_results = xxx
" is sent, where
xxx
is the connection charset that get_charset returns.
Nonzero enables this feature, zero disables it.
Throws an exception if the server doesn't support this, i.e. if
the statement above fails. The MySQL system variable
character_set_results
was added in MySQL 4.1.1.
An error is also thrown if Pike has been compiled with a MySQL client library older than 4.1.0, which lack the necessary support for this.
set_unicode_encode_mode
int get_unicode_decode_mode()
Returns nonzero if unicode decode mode is enabled, zero otherwise.
set_unicode_decode_mode
void set_charset(string charset)
Changes the connection charset. Works similar to sending the query
SET NAMES charset
but also records the charset on the
client side so that various client functions work correctly.
charset is a MySQL charset name or the special value
"unicode"
(see below). You can use SHOW CHARACTER
SET
to get a list of valid charsets.
Specifying "unicode"
as charset is the same as
"utf8"
except that unicode encode and decode modes are
enabled too. Briefly, this means that you can send queries as
unencoded unicode strings and will get back non-binary text
results as unencoded unicode strings. See
set_unicode_encode_mode and set_unicode_decode_mode for
further details.
Throws an exception if the server doesn't support this, i.e. if
the statement SET NAMES
fails. Support for it was added
in MySQL 4.1.0.
If charset is "latin1"
and unicode encode mode is
enabled (the default) then big_query can send wide unicode
queries transparently if the server supports UTF-8. See
set_unicode_encode_mode .
If unicode decode mode is already enabled (see
set_unicode_decode_mode ) then this function won't affect the
result charset (i.e. the MySQL system variable
character_set_results
).
Actually, a query SET character_set_results = utf8
will
be sent immediately after setting the charset as above if
unicode decode mode is enabled and charset isn't
"utf8"
.
You should always use either this function or the
"mysql_charset_name"
option to create to set the
connection charset, or more specifically the charset that the
server expects queries to have (i.e. the MySQL system variable
character_set_client
). Otherwise big_query might not
work correctly.
Afterwards you may change the system variable
character_set_connection
, and also
character_set_results
if unicode decode mode isn't
enabled.
The MySQL latin1
charset is close to Windows
cp1252
. The difference from ISO-8859-1 is a bunch of
printable chars in the range 0x80..0x9f
(which contains
control chars in ISO-8859-1). For instance, the euro currency
sign is 0x80
.
You can use the mysql-latin1
encoding in the
Locale.Charset module to do conversions, or just use the
special "unicode"
charset instead.
get_charset , set_unicode_encode_mode , set_unicode_decode_mode
string get_charset()
Returns the MySQL name for the current connection charset.
Returns "unicode"
if unicode encode mode is enabled and
UTF-8 is used on the server side (i.e. in
character_set_connection
).
In servers with full charset support (i.e. MySQL 4.1.0 or
later), this corresponds to the MySQL system variable
character_set_client
(with one exception - see next
note) and thus controls the charset in which queries are sent.
The charset used for text strings in results might be something
else (and typically is if unicode decode mode is enabled; see
set_unicode_decode_mode ).
If the returned charset is latin1
or unicode
and
unicode encode mode is enabled (the default) then
character_set_client
in the server might be either
latin1
or utf8
, depending on the last sent
query. See set_unicode_encode_mode for more info.
set_charset
string quote(string s)
Quote a string so that it can safely be put in a query.
String to quote.
string latin1_to_utf8(string s)
Converts a string in MySQL latin1
format to UTF-8.
string utf8_encode_query(string q, function(string:string) encode_fn)
Encodes the appropriate sections of the query with encode_fn .
Everything except strings prefixed by an introducer (i.e.
_something
or N
) is encoded.
string encode_time(int time, void|int date)
Converts a system time value to an appropriately formatted time spec for the database.
Time to encode.
If nonzero then time is taken as a "full" unix time spec (where the date part is ignored), otherwise it's converted as a seconds-since-midnight value.
string encode_date(int time)
Converts a system time value to an appropriately formatted date-only spec for the database.
Time to encode.
string encode_datetime(int time)
Converts a system time value to an appropriately formatted date and time spec for the database.
Time to encode.
int decode_time(string timestr, void|int date)
Converts a database time spec to a system time value.
Time spec to decode.
Take the date part from this system time value. If zero, a seconds-since-midnight value is returned.
int decode_date(string datestr)
Converts a database date-only spec to a system time value. Assumes 4-digit years.
Date spec to decode.
int decode_datetime(string timestr)
Converts a database date and time spec to a system time value. Can decode strings missing the time part.
Date and time spec to decode.
Mysql.mysql_result big_query(string query, mapping(string|int:mixed)|void bindings, void|string charset)
Sends a query to the server.
The SQL query.
An optional bindings mapping. See Sql.query for details about this.
An optional charset that will be used temporarily while sending query to the server. If necessary, a query
SET character_set_client=charset
is sent to the server first, then query is sent as-is, and then the connection charset is restored again (if necessary).
Primarily useful with charset set to "latin1"
if
unicode encode mode (see set_unicode_encode_mode ) is enabled
(the default) and you have some large queries (typically blob
inserts) where you want to avoid the query parsing overhead.
A Mysql.mysql_result object is returned if the query is of a kind that returns a result. Zero is returned otherwise.
The individual fields are returned as strings except for NULL, which is returned as UNDEFINED .
Sql.big_query() , big_typed_query() , streaming_query()
Mysql.mysql_result streaming_query(string query, mapping(string|int:mixed)|void bindings, void|string charset)
Makes a streaming SQL query.
This function sends the SQL query query to the Mysql-server. The result of the query is streamed through the returned Mysql.mysql_result object. Note that the involved database tables are locked until all the results has been read.
In all other respects, it behaves like big_query .
big_query() , streaming_typed_query()
Mysql.mysql_result big_typed_query(string query, mapping(string|int:mixed)|void bindings, void|string charset)
Makes a typed SQL query.
This function sends the SQL query query to the Mysql-server.
The types of the result fields depend on the corresponding SQL types. They are mapped as follows:
|
In all other respects, it behaves like big_query .
big_query() , streaming_typed_query()
Mysql.mysql_result streaming_typed_query(string query, mapping(string|int:mixed)|void bindings, void|string charset)
Makes a streaming typed SQL query.
This function acts as the combination of streaming_query() and big_typed_query() .
big_typed_query() , streaming_typed_query()
int(0..1) is_keyword(string name)
Return 1 if the argument name is a mysql keyword that needs to be quoted in a query. The list is currently up-to-date with MySQL 5.1.
CLASS Sql.tds |
The TDS SQL-protocol.
This protocol is used by Sybase and Microsoft's SQL-servers.
Sql.Sql con = Sql.Sql("tds://user:pass@host/database");
Sql.Sql()
void tds_error(string msg, mixed ... args)
Format and report an error.
int insert_id()
Fetch the identity of the last insert (if available).
This performs the query "SELECT @@identity AS insert_id"
.
Returns the identity of the last insert as an integer if available.
Otherwise returns 0
(zero).
string server_info()
Return a string describing the server.
string error()
Return the last error (or possibly the last warning or informational message).
void Sql.tds(string|void server, string|void database, string|void user, string|void password, mapping|void options)
Connect to a remote SQL server via the TDS protocol.
Server to connect to.
Database to connect to.
User to access as.
An explicit domain may be specified by preceeding the user name
with the domain name and a '\\'
.
Password to access with.
Usually accessed via Sql.Sql() .
Sql.Sql()
ENUM Sql.tds.Token |
Tokens that may occur in the answers from the server.
ENUM Sql.tds.EnvType |
Environment types.
Used by TDS_ENV_CHANGE_TOKEN
ENUM Sql.tds.FieldType |
Field types.
CLASS Sql.tds.Connection |
A connection to a TDS server.
Stdio.File Sql.tds.Connection.socket
The actual TCP connection.
InPacket send_packet(Packet p, int flag, int|void last)
Send a packet to the TDS server.
May only be called when the connection is idle.
If last is true an InPacket with the result will be returned.
CLASS Sql.tds.Connection.InPacket |
An incoming packet from the TDS server.
CLASS Sql.tds.Connection.Packet |
An outgoing packet to the TDS server.
CLASS Sql.tds.compile_query |
A compiled query.
void Sql.tds.compile_query(string query)
Compile a query.
big_query()
CLASS Sql.tds.big_query |
A query result set.
int|array(string|int) fetch_row()
Fetch the next row from the result set.
Returns 0
(zero) if all rows have been returned.
Otherwise returns an array(string|int)
with one
entry for each field. If the field is NULL the
entry will be 0
(zero), otherwise the entry
will contain a string representing the value.
array(mapping(string:mixed)) fetch_fields()
Fetch a description of the fields in the result.
Returns an array with a mapping for each of the fields in the result.
The mappings contain the following information:
Standard fields:
|
TDS-specific fields:
|
void Sql.tds.big_query(string|compile_query query)
Execute a query against the database.
The query to execute. This can either be a string, or a compiled query.
compile_query()
CLASS Sql.postgres |
This is an interface to the Postgres (Postgres95, pgsql) database server. This module may or may not be available on your Pike, depending whether the appropriate include and library files could be found at compile-time. Note that you do not need to have a Postgres server running on your host to use this module: you can connect to the database over a TCP/IP socket.
This driver has been deprecated. You should use the more advanced driver Sql.pgsql to access PostgreSQL databases instead.
Also note that this module uses blocking I/O to connect to the server. It is thread-safe, and so it can be used in a multithread environment.
The behavior of the Postgres C API also depends on certain environment variables defined in the environment of the Pike interpreter; some notice and warning notifications might are dumped on stderr.
|
Refer to the Postgres documentation for further details.
Sql.pgsql , Sql.Sql , Postgres.postgres , Sql.postgres_result
inherit Postgres.postgres : mo
void select_db(string dbname)
This function allows you to connect to a database. Due to restrictions of the Postgres frontend-backend protocol, you always have to be connected to a database, so in fact this function just allows you to connect to a different database on the same server.
This function can raise exceptions if something goes wrong (backend process not running, not enough permissions..)
create
string error()
This function returns the textual description of the last
server-related error. Returns 0
if no error has occurred
yet. It is not cleared upon reading (can be invoked multiple
times, will return the same result until a new error occurs).
big_query
string host_info()
This function returns a string describing what host are we talking to, and how (TCP/IP or UNIX sockets).
void reset()
This function resets the connection to the backend. Can be used for a variety of reasons, for example to detect the status of a connection.
This function is Postgres-specific, and thus it is not available through the generic SQL-interface.
string Sql.postgres.version
Should you need to report a bug to the author, please submit along with the report the driver version number, as returned by this call.
void Sql.postgres()
void Sql.postgres(string host, void|string database, void|string user, void|string password, void|mapping options)
With no arguments, this function initializes (reinitializes if a connection had been previously set up) a connection to the Postgres backend. Since Postgres requires a database to be selected, it will try to connect to the default database. The connection may fail however for a variety of reasons, in this case the most likely of all is because you don't have enough authority to connect to that database. So use of this particular syntax is discouraged.
The host argument can have the syntax "hostname"
or
"hostname:portname"
. This allows to specify the TCP/IP
port to connect to. If it is 0
or ""
, it will try
to connect to localhost, default port.
The database argument specifies the database to connect to. If
0
or ""
, it will try to connect to the specified
database.
The username and password arguments are silently ignored, since the Postgres C API doesn't allow to connect to the server as any user different than the user running the interface.
You need to have a database selected before using the sql-object, otherwise you'll get exceptions when you try to query it. Also notice that this function can raise exceptions if the db server doesn't respond, if the database doesn't exist or is not accessible by you.
You don't need bothering about syncronizing the connection to the database: it is automatically closed (and the database is sync-ed) when the object is destroyed.
Sql.pgsql , Postgres.postgres , Sql.Sql , postgres->select_db
void set_notify_callback()
void set_notify_callback(function f)
void set_notify_callback(function f, int|float poll_delay)
With Postgres you can associate events and notifications to tables. This function allows you to detect and handle such events.
With no arguments, resets and removes any callback you might have put previously, and any polling cycle.
With one argument, sets the notification callback (there can be only one for each sqlobject).
With two arguments, sets a notification callback and sets a polling cycle.
The polling cycle is necessary because of the way notifications are delivered, that is piggyback with a query result. This means that if you don't do any query, you'll receive no notification. The polling cycle starts a call_out cycle which will do an empty query when the specified interval expires, so that pending notifications may be delivered.
The callback function must return no value, and takes a string argument, which will be the name of the table on which the notification event has occurred. In future versions, support for user-specified arguments will be added.
The polling cycle can be run only if your process is in "event-driven mode" (that is, if 'main' has returned a negative number).
This function is Postgres-specific, and thus it is not available through the generic SQL-interface.
An integer can be passed as first argument, but it's effect is not documented.
void create_db(string db)
This function creates a new database with the given name (assuming we have enough permissions to do this).
drop_db
void drop_db(string db)
This function destroys a database and all the data it contains (assuming we have enough permissions to do so).
create_db
string server_info()
This function returns a string describing the server we are
talking to. It has the form "servername/serverversion"
(like the HTTP protocol description) and is most useful in
conjunction with the generic SQL-server module.
array(string) list_dbs(void|string glob)
Lists all the databases available on the server. If glob is specified, lists only those databases matching it.
array(string) list_tables(void|string glob)
Returns an array containing the names of all the tables in the currently selected database. If a glob is specified, it will return only those tables whose name matches it.
array(mapping(string:mixed)) list_fields(string table, void|string wild)
Returns a mapping, indexed on the column name, of mappings describing the attributes of a table of the current database. If a glob is specified, will return descriptions only of the columns matching it.
The currently defined fields are:
|
int|object big_query(object|string q, mapping(string|int:mixed)|void bindings)
This is the only provided interface which allows you to query the database. If you wish to use the simpler "query" function, you need to use the Sql.Sql generic SQL-object.
It returns a postgres_result object (which conforms to the Sql.sql_result standard interface for accessing data). I recommend using query() for simpler queries (because it is easier to handle, but stores all the result in memory), and big_query() for queries you expect to return huge amounts of data (it's harder to handle, but fetches results on demand).
This function can raise exceptions.
Sql.Sql , Sql.sql_result
int|object streaming_query(object|string q, mapping(string|int:mixed)|void bindings)
This is an alias for big_query() , since big_query() already supports streaming.
big_query , Sql.Sql , Sql.sql_result
inherit Sql.pgsql : pgsql
Maps SQL-urls for postgres://[user[:password]@][hostname][:port][/database] onto pgsql://[user[:password]@][hostname][:port][/database]
The reason this happens, is because Pike was compiled without libpq support, therefore Pike falls back to the faster, smaller memory footprint, more advanced and native PostgreSQL driver called Sql.pgsql .
Sql.pgsql , Sql.Sql
CLASS Sql.pgsqls |
Implements SQL-urls for pgsqls://[user[:password]@][hostname][:port][/database]
Sets the connection to SSL-mode, otherwise identical to Sql.pgsql .
Sql.pgsql , Sql.Sql
inherit Sql.pgsql : pgsql
CLASS Sql.pgsql |
This is an interface to the PostgreSQL database server. This module is independent of any external libraries. Note that you do not need to have a PostgreSQL server running on your host to use this module: you can connect to the database over a TCP/IP socket.
This module replaces the functionality of the older Sql.postgres and Postgres.postgres modules.
This module supports the following features:
PostgreSQL network protocol version 3, authentication methods currently supported are: cleartext and MD5 (recommended).
Streaming queries which do not buffer the whole resultset in memory.
Automatic binary transfers to and from the database for most common datatypes (amongst others: integer, text and bytea types).
Automatic character set conversion and native wide string support. Supports UTF8/Unicode for multibyte characters, and all single-byte character sets supported by the database.
SQL-injection protection by allowing just one statement per query and ignoring anything after the first (unquoted) semicolon in the query.
COPY support for streaming up- and download.
Accurate error messages.
Automatic precompilation of complex queries (session cache).
Multiple simultaneous queries on the same database connection.
Cancelling of long running queries by force or by timeout.
Event driven NOTIFY.
SSL encrypted connections (optional or forced).
Check the PostgreSQL documentation for further details.
Multiple simultaneous queries on the same database connection is a feature that none of the other database drivers for Pike support. So, although it's efficient, its use will make switching database drivers difficult.
Sql.Sql , Sql.postgres , http://www.postgresql.org/docs/
void Sql.pgsql()
void Sql.pgsql(string host, void|string database, void|string user, void|string password, void|mapping(string:mixed) options)
With no arguments, this function initialises (reinitialises if a connection has been set up previously) a connection to the PostgreSQL backend. Since PostgreSQL requires a database to be selected, it will try to connect to the default database. The connection may fail however, for a variety of reasons; in this case the most likely reason is because you don't have sufficient privileges to connect to that database. So use of this particular syntax is discouraged.
Should either contain "hostname"
or
"hostname:portname"
. This allows you to specify the TCP/IP
port to connect to. If the parameter is 0
or ""
,
it will try to connect to localhost, default port.
Specifies the database to connect to. Not specifying this is only supported if the PostgreSQL backend has a default database configured. If you do not want to connect to any live database, you can use template1 .
Currently supports at least the following:
|
For the numerous other options please check the PostgreSQL manual.
You need to have a database selected before using the sql-object, otherwise you'll get exceptions when you try to query it. Also notice that this function can raise exceptions if the db server doesn't respond, if the database doesn't exist or is not accessible by you.
Postgres.postgres , Sql.Sql , select_db() , http://www.postgresql.org/search/?u=%2Fdocs%2Fcurrent%2F&q=client+connection+defaults
string error(void|int clear)
The textual description of the last
server-related error. Returns 0
if no error has occurred
yet. It is not cleared upon reading (can be invoked multiple
times, will return the same result until a new error occurs).
During the execution of a statement, this function accumulates all non-error messages (notices, warnings, etc.). If a statement does not generate any errors, this function will return all collected messages from the last statement.
The string returned is not newline-terminated.
To clear the error, set it to 1
.
big_query()
string host_info()
This function returns a string describing what host are we talking to, and how (TCP/IP or UNIX sockets).
server_info()
int is_open()
Returns true if the connection seems to be open.
This function only checks that there's an open connection, and that the other end hasn't closed it yet. No data is sent over the connection.
For a more reliable check of whether the connection is alive, please use ping() .
ping()
int ping()
Check whether the connection is alive.
Returns one of the following:
|
is_open()
void cancelquery()
Cancels the currently running query.
reload() , resync()
This function is PostgreSQL-specific, and thus it is not available through the generic SQL-interface.
void set_charset(string charset)
Changes the connection charset. When set to UTF8 , the query, parameters and results can be Pike-native wide strings.
A PostgreSQL charset name.
get_charset() , create() , http://www.postgresql.org/search/?u=%2Fdocs%2Fcurrent%2F&q=character+sets
string get_charset()
The PostgreSQL name for the current connection charset.
set_charset() , getruntimeparameters() , http://www.postgresql.org/search/?u=%2Fdocs%2Fcurrent%2F&q=character+sets
mapping(string:string) getruntimeparameters()
Currently active runtimeparameters for the open session; these are initialised by the options parameter during session creation, and then processed and returned by the server. Common values are:
|
The values can be changed during a session using SET commands to the database. For other runtimeparameters check the PostgreSQL documentation.
http://www.postgresql.org/search/?u=%2Fdocs%2Fcurrent%2F&q=client+connection+defaults
This function is PostgreSQL-specific, and thus it is not available through the generic SQL-interface.
mapping(string:mixed) getstatistics()
A set of statistics for the current session:
|
This function is PostgreSQL-specific, and thus it is not available through the generic SQL-interface.
int setcachedepth(void|int newdepth)
Sets the new cachedepth for automatic caching of prepared statements.
The previous cachedepth.
This function is PostgreSQL-specific, and thus it is not available through the generic SQL-interface.
int settimeout(void|int newtimeout)
Sets the new timeout for long running queries.
The previous timeout.
This function is PostgreSQL-specific, and thus it is not available through the generic SQL-interface.
int setportalbuffersize(void|int newportalbuffersize)
Sets the new portalbuffersize for buffering partially concurrent queries.
The previous portalbuffersize.
This function is PostgreSQL-specific, and thus it is not available through the generic SQL-interface.
int setfetchlimit(void|int newfetchlimit)
Sets the new fetchlimit to interleave queries.
The previous fetchlimit.
This function is PostgreSQL-specific, and thus it is not available through the generic SQL-interface.
void close()
Closes the connection to the database, any running queries are terminated instantly.
This function is PostgreSQL-specific, and thus it is not available through the generic SQL-interface.
void reload()
For PostgreSQL this function performs the same function as resync() .
resync() , cancelquery()
void resync()
Resyncs the database session; typically used to make sure the session is not still in a dangling transaction.
If called while queries/portals are still in-flight, this function is a no-op.
If called while the connection is in idle state, the function is lightweight and briefly touches base with the database server to make sure client and server are in sync.
If issued while inside a transaction, it will rollback the transaction, close all open cursors, drop all temporary tables and reset all session variables to their default values.
cancelquery() , reload()
This function is PostgreSQL-specific, and thus it is not available through the generic SQL-interface.
void select_db(string dbname)
This function allows you to connect to a database. Due to restrictions of the Postgres frontend-backend protocol, you always have to be connected to a database, so in fact this function just allows you to connect to a different database on the same server.
This function can raise exceptions if something goes wrong (backend process not running, insufficient privileges...)
create()
void set_notify_callback(string condition, void|function(int:void) notify_cb, void|int selfnotify, mixed ... args)
With PostgreSQL you can LISTEN to NOTIFY events. This function allows you to detect and handle such events.
Name of the notification event we're listening to. A special case is the empty string, which matches all events, and can be used as fallback function which is called only when the specific condition is not handled. Another special case is _reconnect which gets called whenever the connection unexpectedly drops and reconnects to the database.
Function to be called on receiving a notification-event of
condition condition .
The callback function is invoked with
void notify_cb(pid,condition,extrainfo, .. args);
pid is the process id of the database session that originated
the event. condition contains the current condition.
extrainfo contains optional extra information specified by
the database.
The rest of the arguments to notify_cb are passed
verbatim from args .
The callback function must return no value.
Normally notify events generated by your own session are ignored. If you want to receive those as well, set selfnotify to one.
Extra arguments to pass to notify_cb .
This function is PostgreSQL-specific, and thus it is not available through the generic SQL-interface.
string quote(string s)
The given string, but escapes/quotes all contained magic characters according to the quoting rules of the current session for non-binary arguments in textual SQL-queries.
Quoting must not be done for parameters passed in bindings.
big_query() , quotebinary() , create()
string quotebinary(string s)
The given string, but escapes/quotes all contained magic characters for binary (bytea) arguments in textual SQL-queries.
Quoting must not be done for parameters passed in bindings.
big_query() , quote()
This function is PostgreSQL-specific, and thus it is not available through the generic SQL-interface.
void create_db(string db)
This function creates a new database (assuming we have sufficient privileges to do this).
Name of the new database.
drop_db()
void drop_db(string db)
This function destroys a database and all the data it contains (assuming we have sufficient privileges to do so). It is not possible to delete the database you're currently connected to. You can connect to database template1 to avoid connecting to any live database.
Name of the database to be deleted.
create_db()
string server_info()
A string describing the server we are
talking to. It has the form "servername/serverversion"
(like the HTTP protocol description) and is most useful in
conjunction with the generic SQL-server module.
host_info()
array(string) list_dbs(void|string glob)
An array of the databases available on the server.
If specified, list only those databases matching it.
array(string) list_tables(void|string glob)
An array containing the names of all the tables and views in the path in the currently selected database.
If specified, list only the tables with matching names.
array(mapping(string:mixed)) list_fields(void|string table, void|string glob)
A mapping, indexed on the column name, of mappings describing the attributes of a table of the current database. The currently defined fields are:
|
If specified, list only the tables with matching names.
Setting it to *
will include system columns in the list.
string status_commit()
The current commitstatus of the connection. Returns either one of:
|
This function is PostgreSQL-specific, and thus it is not available through the generic SQL-interface.
Sql.pgsql_util.pgsql_result big_query(string query)
Sql.pgsql_util.pgsql_result big_query(string query, mapping bindings)
This is the only provided interface which allows you to query the database. If you wish to use the simpler Sql.Sql()->query() function, you need to use the Sql.Sql generic SQL-object.
Bindings are supported natively straight across the network. Special bindings supported are:
|
A Sql.pgsql_util.pgsql_result object (which conforms to the Sql.sql_result standard interface for accessing data). It is recommended to use Sql.Sql()->query() for simpler queries (because it is easier to handle, but stores all the result in memory), and Sql.Sql()->big_query() for queries you expect to return huge amounts of data (it's harder to handle, but fetches results on demand).
This function can raise exceptions.
This function supports multiple simultaneous queries (portals) on a single database connection. This is a feature not commonly supported by other database backends.
This function, by default, does not support multiple queries in one querystring. I.e. it allows for but does not require a trailing semicolon, but it simply ignores any commands after the first unquoted semicolon. This can be viewed as a limited protection against SQL-injection attacks. To make it support multiple queries in one querystring, use the :_text option.
big_typed_query() , Sql.Sql , Sql.sql_result , Sql.Sql()->query() , Sql.pgsql_util.pgsql_result
object streaming_query(string q, void|mapping(string|int:mixed) bindings)
This is an alias for big_query() , since big_query() already supports streaming of multiple simultaneous queries through the same connection.
big_query() , big_typed_query() , Sql.Sql , Sql.sql_result
object big_typed_query(string q, void|mapping(string|int:mixed) bindings)
This function returns an object that allows streaming and typed results.
big_query() , Sql.Sql , Sql.sql_result
CLASS Sql.null |
The NULL Sql handler.
This is an empty Sql handler typically used to test other functionality of the Sql module.
string quote(string s)
sprintf ("quote(%q)", s)
.
array(mapping(string:mixed)) query(string query, mapping(string:mixed)|void bindings)
Returns an array with a single element:
|
CLASS Sql.postgres_result |
Sql.postgres_result contains the result of a Postgres-query. See Sql.postgres for a description of this program's functions.
inherit Postgres.postgres_result : postgres_result
CLASS Sql.sqlite |
Low-level interface to SQLite3 databases.
This class should typically not be accessed directly, but instead
via Sql.Sql() with the scheme "sqlite://"
.
int insert_id()
Returns the value of the ROWID (aka OID, aka _ROWID_,
or declared INTEGER PRIMARY KEY) column for the most recent
successful INSERT operation, or 0
(zero) if no INSERT
operations have been performed on the connection yet.
CLASS Sql.sqlite.ResObj |
Result object from big_query() .
Module Sql.pgsql_util |
Some pgsql utility functions
CLASS Sql.pgsql_util.pgsql_result |
The result object returned by Sql.pgsql()->big_query() , except for the noted differences it behaves the same as Sql.sql_result .
Sql.sql_result , Sql.pgsql , Sql.Sql , Sql.pgsql()->big_query()
string status_command_complete()
Returns the command-complete status for this query.
affected_rows()
This function is PostgreSQL-specific, and thus it is not available through the generic SQL-interface.
int affected_rows()
Returns the number of affected rows by this query.
status_command_complete()
This function is PostgreSQL-specific, and thus it is not available through the generic SQL-interface.
int num_fields()
Sql.sql_result()->num_fields()
int num_rows()
Sql.sql_result()->num_rows()
int eof()
Sql.sql_result()->eof()
array(mapping(string:mixed)) fetch_fields()
Sql.sql_result()->fetch_fields()
array(mixed) fetch_row()
void fetch_row(string|array(string) copydatasend)
One result row at a time.
When using COPY FROM STDOUT, this method returns one row at a time as a single string containing the entire row.
When using COPY FROM STDIN, this method accepts a string or an array of strings to be processed by the COPY command; when sending the amount of data sent per call does not have to hit row or column boundaries.
The COPY FROM STDIN sequence needs to be completed by either explicitly or implicitly destroying the result object, or by passing a zero argument to this method.
eof()
Module Sql.sql_util |
Some SQL utility functions
string quote(string s)
Quote a string so that it can safely be put in a query.
String to quote.
void fallback()
Throw an error in case an unimplemented function is called.
string emulate_bindings(string query, mapping(string|int:mixed)|void bindings, void|object driver)
Build a raw SQL query, given the cooked query and the variable bindings It's meant to be used as an emulation engine for those drivers not providing such a behaviour directly (i.e. Oracle). The raw query can contain some variables (identified by prefixing a colon to a name or a number (i.e. ":var" or ":2"). They will be replaced by the corresponding value in the mapping.
The query.
Optional mapping containing the variable bindings. Make sure that no confusion is possible in the query. If necessary, change the variables' names.
CLASS Sql.sql_util.UnicodeWrapper |
Result object wrapper performing utf8 decoding of all fields.
protected object Sql.sql_util.UnicodeWrapper.master_resultvoid Sql.sql_util.UnicodeWrapper(object master_result)
int num_rows()
Returns the number of rows in the result.
int num_fields()
Returns the number of fields in the result.
int(0..1) eof()
Returns 1
if there are no more rows in the result.
protected array(int|mapping(string:mixed)) Sql.sql_util.UnicodeWrapper.field_info
Cached fetch_fields() result.
array(int|mapping(string:mixed)) fetch_fields()
Returns Information about the fields in the result.
The following fields are converted from UTF8 if present:
|
void seek(int rows)
Skip ahead the specified number of rows.
int|array(string) fetch_row()
Fetch the next row from the result.
All strings in the result are decoded from UTF8.
int|string fetch_json_result()
JSON is always utf8 default, do nothing.
CLASS Sql.sql_util.MySQLUnicodeWrapper |
Result wrapper for MySQL that performs UTF-8 decoding of all nonbinary fields. Useful if the result charset of the connection has been set to UTF-8.
There's normally no need to use this class directly. It's used automatically when Mysql.set_unicode_decode_mode is activated.
inherit UnicodeWrapper : UnicodeWrapper
Module Mysql |
This module enables access to the Mysql database from within Pike. Use Sql.Sql for general database access.
Mysql is available from http://www.mysql.com.
Mysql.mysql , Mysql.mysql_result , Sql.Sql
CLASS Mysql.mysql_result |
Objects of this class contain the result from Mysql queries.
Mysql.mysql , Mysql.mysql->big_query()
void Mysql.mysql_result(Mysql.mysql connection)
Make a new Mysql.mysql_result object.
Mysql.mysql->big_query() , Mysql.mysql->list_dbs() , Mysql.mysql->list_tables() , Mysql.mysql->list_processes() , Mysql.mysql
int num_rows()
Number of rows in the result.
num_fields()
int num_fields()
Number of fields in the result.
num_rows()
void field_seek(int field_no)
Skip to specified field.
Places the field cursor at the specified position. This affects which field mysql_result->fetch_field() will return next.
Fields are numbered starting with 0.
This function is usually not enabled. To enable it SUPPORT_FIELD_SEEK must be defined when compiling the mysql-module.
fetch_field() , fetch_fields()
int(0..1) eof()
Sense end of result table.
Returns 1
when all rows have been read, and 0
(zero)
otherwise.
fetch_row()
int|mapping(string:mixed) fetch_field()
Return specification of the current field.
Returns a mapping with information about the current field, and
advances the field cursor one step. Returns 0
(zero) if
there are no more fields.
The mapping contains the same entries as those returned by
Mysql.mysql->list_fields() , except that the entry "default"
is missing.
This function is usually not enabled. To enable it SUPPORT_FIELD_SEEK must be defined when compiling the mysql-module.
fetch_fields() , field_seek() , Mysql.mysql->list_fields()
array(int|mapping(string:mixed)) fetch_fields()
Get specification of all remaining fields.
Returns an array with one mapping for every remaining field in the result table.
The returned data is similar to the data returned by
Mysql.mysql->list_fields() , except for that the entry
"default"
is missing.
Resets the field cursor to 0
(zero).
This function always exists even when fetch_field() and field_seek() don't.
fetch_field() , field_seek() , Mysql.mysql->list_fields()
void seek(int rows)
Skip ahead rows rows.
Can only seek forward.
fetch_row()
int|array(string) fetch_row()
Fetch the next row from the result.
Returns an array with the contents of the next row in the result. Advances the row cursor to the next now.
Returns 0
(zero) at the end of the table.
seek()
string fetch_json_result()
Fetch all remaining rows and return them as JSON-encoded data.
fetch_row()
Ensure that all fields (including binary fields) are UTF-8 encoded.
CLASS Mysql.mysql |
Interface to the Mysql database.
This class enables access to the Mysql database from within Pike.
Mysql is available from http://www.mysql.com.
Mysql.mysql_result , Sql.Sql
void Mysql.mysql()
void Mysql.mysql(string host)
void Mysql.mysql(string host, string database)
void Mysql.mysql(string host, string database, string user)
void Mysql.mysql(string host, string database, string user, string password)
void Mysql.mysql(string host, string database, string user, string password, mapping(string:string|int) options)
Connect to a Mysql database.
To access the Mysql database, you must first connect to it. This is done with this function.
If you give no argument, or give ""
as host it will connect
with a UNIX-domain socket, which can be a big performance gain.
This optional mapping can contain zero or more of the following parameters:
|
Some options may not be implemented. Unimplemented options are silently ignored.
To use SSL-connections, set the SSL-parameters correctly. They correspond to the parameters given to the mysql-client with the same name so make sure that the mysql-client works with SSL and set these parameters to the same values and everything should work. If SSL-options are loaded from a config-file, one may set the connect_options to include CLIENT_SSL.
If Pike has been built with an old MySQL client lib then it
might not be possible to specify some charsets that the server
supports with the "mysql_charset_name"
option. In such
cases it's possible that set_charset works better (provided
the server is 4.1 or newer).
string _sprintf(int type, void|mapping flags)
int is_open()
Returns true if the connection seems to be open.
This function only checks that there's an open connection, and that the other end hasn't closed it yet. No data is sent over the connection.
For a more reliable check of whether the connection is alive, please use ping() .
ping()
int ping()
Check whether the connection is alive.
Returns one of the following:
|
is_open()
int affected_rows()
Returns the number of rows affected by the last query.
int insert_id()
Returns the id of the last INSERT query into a table with an AUTO INCREMENT field.
string error()
Returns a string describing the last error from the Mysql-server.
Returns 0
(zero) if there was no error.
void select_db(string database)
Select database.
The Mysql-server can hold several databases. You select which one you want to access with this function.
create() , create_db() , drop_db()
void create_db(string database)
Create a new database
This function creates a new database named database in the Mysql-server.
select_db() , drop_db()
void drop_db(string database)
Drop a database
This function drops the database named database from the Mysql-server.
create_db() , select_db()
void shutdown()
Shutdown the Mysql-server
This function shuts down a running Mysql-server.
reload()
void reload()
Reload security tables
This function causes the Mysql-server to reload its access tables.
shutdown()
string statistics()
Some Mysql-server statistics
This function returns some server statistics.
server_info() , host_info() , protocol_info()
string server_info()
Get the version number of the Mysql-server.
statistics() , host_info() , protocol_info()
string host_info()
Get information about the Mysql-server connection
statistics() , server_info() , protocol_info()
int protocol_info()
Give the Mysql protocol version
This function returns the version number of the protocol the Mysql-server uses.
statistics() , server_info() , host_info()
Mysql.mysql_result list_dbs()
Mysql.mysql_result list_dbs(string wild)
List databases
Returns a table containing the names of all databases in the Mysql-server. If the argument wild is specified, only those matching it will be returned.
list_tables() , list_fields() , list_processes() , Mysql.mysql_result
Mysql.mysql_result list_tables()
Mysql.mysql_result list_tables(string wild)
List tables in the current database
Returns a table containing the names of all tables in the current database. If the argument wild is given, only those matching it will be returned.
list_dbs() , list_fields() , list_processes() , Mysql.mysql_result
array(int|mapping(string:mixed)) list_fields(string table)
array(int|mapping(string:mixed)) list_fields(string table, string wild)
List all fields.
Returns an array of mappings with information about the fields in the table named table . If the argument wild is given, only those fields matching it will be returned
The mappings contain the following entries:
|
The type of the field can be any of:
"decimal"
, "char"
, "short"
, "long"
,
"float"
, "double"
, "null"
, "time"
,
"longlong"
, "int24"
, "tiny blob"
,
"medium blob"
,
"long blob"
, "var string"
, "string"
or
"unknown"
.
The flags multiset can contain any of:
|
Michael Widenius recomends use of the following query instead: show fields in 'table' like "wild".
list_dbs() , list_tables() , list_processes() , Mysql.mysql_result.fetch_field()
Mysql.mysql_result list_processes()
List all processes in the Mysql-server
Returns a table containing the names of all processes in the Mysql-server.
list_dbs() , list_tables() , list_fields() , Mysql.mysql_result
int binary_data()
Inform if this version of Mysql.mysql supports binary data
This function returns non-zero if binary data can be reliably stored and retreived with this version of the mysql-module.
Usually, there is no problem storing binary data in mysql-tables,
but data containing '\0'
(NUL) couldn't be fetched with old
versions (prior to 3.20.5) of the mysql-library.
Module Postgres |
CLASS Postgres.postgres |
This is an interface to the Postgres database server using libpq. This module may or may not be available on your Pike, depending whether the appropriate include and library files could be found at compile-time. Note that you do not need to have a Postgres server running on your host to use this module: you can connect to the database over a TCP/IP socket.
Please notice that unless you wish to specifically connect to a Postgres server, you'd better use the Sql.Sql , which is a server-independent sql-server-class. The interfaces to all existing sql-classes are consistent. Using Sql.Sql ensures that your Pike applications will run with any supported SQL server without changing a single line of code, at least for most common (and simple) operations.
The program Postgres.postgres provides the raw interface to the database. Many functions are not available for this program. Therefore, its use is DEPRECATED. It is included in this documentation only for completeness' sake. Use Sql.postgres instead, or even better Sql.Sql
This driver is based on libpq and is DEPRECATED. There is a newer driver called Sql.pgsql which is faster and more robust than this driver and does not depend on any libraries.
There is no testsuite for this module, since to test anything would require a working Postgres server. You can try to use the included scripts in the "pike/src/modules/Postgres/extras" directory but you'll probably have to patch them to reflect your site's settings.
The behavior of the Postgres C API also depends on certain environment variables defined in the environment of the pike interpreter.
|
Refer to the libpq documentation for further details.
Sql.Sql , Sql.postgres , Sql.postgres_result
string Postgres.postgres.version
Should you need to report a bug to the author, please submit along with the report the driver version number, as returned by this call.
void Postgres.postgres()
void Postgres.postgres(string host, void|string database, void|int port)
With no arguments, this function initializes (reinitializes if a connection had been previously set up) a connection to the Postgres backend. Since Postgres requires a database to be selected, it will try to connect to the default database. The connection may fail however for a variety of reasons, in this case the most likely of all is because you don't have enough authority to connect to that database. So use of this particular syntax is discouraged.
The host argument allows you to connect to databases residing on different hosts. If it is 0 or "", it will try to connect to localhost.
The database argument specifies the database to connect to. If 0 or "", it will try to connect to the default database.
You need to have a database selected before using the sql-object, otherwise you'll get exceptions when you try to query it. Also notice that this function can raise exceptions if the db server doesn't respond, if the database doesn't exist or is not accessible by you.
You don't need bothering about syncronizing the connection to the database: it is automatically closed (and the database is sync-ed) when the object is destroyed.
Sql.postgres , Sql.Sql , select_db
void select_db(string dbname)
This function allows you to connect to a database. Due to restrictions of the Postgres frontend-backend protocol, you always have to be connected to a database, so in fact this function just allows you to connect to a different database on the same server.
This function can raise exceptions if something goes wrong (backend process not running, not enough permissions..)
create
Sql.postgres_result big_query(string sqlquery)
This is the only provided interface which allows you to query the database. If you wish to use the simpler "query" function, you need to use the Sql.Sql generic sql-object.
It returns a postgres_result object (which conforms to the Sql.sql_result standard interface for accessing data). I recommend using query() for simpler queries (because it is easier to handle, but stores all the result in memory), and big_query for queries you expect to return huge amounts of data (it's harder to handle, but fectches results on demand).
This function can raise exceptions.
The program Sql.postgres_result is a superset of the raw Postgres.postgres_result which does not do chunking to avoid excessive memory usage in case of large resultsets.
Sql.Sql , Sql.sql_result
string error()
This function returns the textual description of the last server-related error. Returns 0 if no error has occurred yet. It is not cleared upon reading (can be invoked multiple times, will return the same result until a new error occurs).
big_query
void reset()
This function resets the connection to the backend. Can be used for a variety of reasons, for example to detect the status of a connection.
This function is Postgres-specific, and thus it is not available through the generic SQL-interface.
void _set_notify_callback()
void _set_notify_callback(function f)
With Postgres you can associate events and notifications to tables. This function allows you to detect and handle such events.
With no arguments, resets and removes any callback you might have put previously, and any polling cycle.
With one argument, sets the notification callback (there can be only one for each sqlobject).
The callback function must return no value, and takes a string argument, which will be the name of the table on which the notification event has occurred. In future versions, support for user-specified arguments will be added.
The Sql.postgres program adds support for automatic delivery of messages (see it for explanation on the inner workings of this feature).
This function is Postgres-specific, and thus it is not available through the generic SQL-interface
Sql.postgres
string host_info()
This function returns a string describing what host are we talking to, and how (TCP/IP or UNIX sockets).
int affected_rows()
This function returns the number of rows affected by the last query.
string _quote(string s)
Escape a string to prevent SQL injection, using the current connection's character encoding settings.
CLASS Postgres.postgres_result |
Contains the result of a Postgres-query.
Sql.postgres, Postgres.postgres, Sql.Sql, Sql.sql_result
void Postgres.postgres_result(object o)
You can't create istances of this object yourself. The only way to create it is via a big_query to a Postgres database.
int num_rows()
Returns the number of rows in the result.
int num_fields()
Returns the number of fields in the result.
array(mapping(string:mixed)) fetch_fields()
Returns an array with an entry for each field, each entry is a mapping with the following fields:
|
For char() fields, length is to be intended as the MAXIMUM length of the field. This is not part of the interface specifications in fact, but a driver-choice. In fact char() fields are for Postgres _FIXED_ length fields, and are space-padded. If CUT_TRAILING_SPACES is defined when the driver is compiled (default behavior) it will cut such spaces.
void seek()
Moves the result cursor (ahead or backwards) the specified number of rows. Notice that when you fetch a row, the cursor is automatically moved forward one slot.
array(string) fetch_row()
Returns an array with the contents of the next row in the result. Advances the row cursor to the next row. Returns 0 at end of table.
Since there's no generic way to know whether a type is numeric or not in Postgres, all results are returned as strings. You can typecast them in Pike to get the numeric value.
seek()
Module Gdbm |
CLASS Gdbm.gdbm |
void Gdbm.gdbm(void|string file, void|string mode)
Without arguments, this function does nothing. With one argument it opens the given file as a gdbm database, if this fails for some reason, an error will be generated. If a second argument is present, it specifies how to open the database using one or more of the follow flags in a string:
|
The fast mode prevents the database from syncronizing each change in the database immediately. This is dangerous because the database can be left in an unusable state if Pike is terminated abnormally.
The default mode is "rwc"
.
The gdbm manual states that it is important that the database is closed properly. Unfortunately this will not be the case if Pike calls exit() or returns from main(). You should therefore make sure you call close or destruct your gdbm objects when exiting your program. This will probably be done automatically in the future.
string fetch(string key)
string `[](string key)
Return the data associated with the key 'key' in the database. If there was no such key in the database, zero is returned.
int(0..1) delete(string key)
Remove a key from the database. Returns 1 if successful, otherwise 0, e.g. when the item is not present or the database is read only.
string firstkey()
Return the first key in the database, this can be any key in the database.
string nextkey(string key)
This returns the key in database that follows the key 'key' key. This is of course used to iterate over all keys in the database.
// Write the contents of the database for(key=gdbm->firstkey(); k; k=gdbm->nextkey(k)) write(k+":"+gdbm->fetch(k)+"\n");
string `[]=(string key, string data)
Associate the contents of 'data' with the key 'key'. If the key 'key' already exists in the database the data for that key will be replaced. If it does not exist it will be added. An error will be generated if the database was not open for writing.
gdbm[key] = data;
Returns data on success.
store()
int store(string key, string data)
Associate the contents of 'data' with the key 'key'. If the key 'key' already exists in the database the data for that key will be replaced. If it does not exist it will be added. An error will be generated if the database was not open for writing.
gdbm->store(key, data);
Returns 1
on success.
Note that the returned value differs from that of `[]=() .
`[]=()
int reorganize()
Deletions and insertions into the database can cause fragmentation which will make the database bigger. This routine reorganizes the contents to get rid of fragmentation. Note however that this function can take a LOT of time to run.
void sync()
When opening the database with the 'f' flag writings to the database can be cached in memory for a long time. Calling sync will write all such caches to disk and not return until everything is stored on the disk.
void close()
Closes the database.