PostgreSQL functionsPostgreSQL
Postgres, developed originally in the UC Berkeley Computer Science
Department, pioneered many of the object-relational concepts now
becoming available in some commercial databases. It provides
SQL92/SQL99 language support, transaction integrity and type
extensibility. PostgreSQL is an open source descendant of this
original Berkeley code.
PostgreSQL database is Open Source product and available without
cost. To use PostgreSQL support, you need PostgreSQL 6.5 or
later. PostgreSQL 7.0 or later to enable all PostgreSQL module
feature. PostgreSQL supports many character encoding including
multibyte character encoding. The current version and more
information about PostgreSQL is available at &url.pgsql;.
In order to enable PostgreSQL support,
is required when you compile
PHP. If shared object module is available, PostgreSQL module may
be loaded using extension
directive in &php.ini; or dl
function. Supported ini directives are described in
php.ini-dist which comes with source distribution.
Using the PostgreSQL module with PHP 4.0.6 is not recommended due to
a bug in the notice message handling code. Use 4.1.0 or later.
PostgreSQL function names will be changed in 4.2.0 release to
confirm to current coding standards. Most of new names will have
additional underscores, e.g. pg_lo_open(). Some functions are
renamed to different name for consistency. e.g. pg_exec() to
pg_query(). Older names can be used in 4.2.0 and a few releases
from 4.2.0, but they may be deleted in the future.
Function names changedOld nameNew namepg_execpg_querypg_getlastoidpg_last_oidpg_cmdtuplespg_affected_rowspg_numrowspg_num_rowspg_numfieldspg_num_fieldspg_fieldnamepg_field_namepg_fieldsizepg_field_sizepg_fieldnumpg_field_numpg_fieldprtlenpg_field_prtlenpg_fieldisnullpg_field_is_nullpg_freeresultpg_free_resultpg_resultpg_fetch_resultpg_loreadallpg_lo_read_allpg_locreatepg_lo_createpg_lounlinkpg_lo_unlinkpg_loopenpg_lo_openpg_loclosepg_lo_closepg_loreadpg_lo_readpg_lowritepg_lo_writepg_loimportpg_lo_importpg_loexportpg_lo_export
The old pg_connect/pg_pconnect
syntax will be deprecated to support asynchronous connections in the
future. Please use a connection string for pg_connect
and pg_pconnect.
Not all functions are supported by all builds. It depends on your
libpq (The PostgreSQL C Client interface) version and how libpq is
compiled. If there is missing function, libpq does not support
the feature required for the function.
It is also important that you use newer libpq than PostgreSQL
Server to be connected. If you use libpq older than PostgreSQL
Server expects, you may have problems.
Since version 6.3 (03/02/1998) PostgreSQL uses unix domain sockets
by default. TCP port will NOT be opened by default. A table is
shown below describing these new connection possibilities. This
socket will be found in /tmp/.s.PGSQL.5432.
This option can be enabled with the '-i' flag to
postmaster and it's meaning is: "listen on
TCP/IP sockets as well as Unix domain sockets".
Postmaster and PHPPostmasterPHPStatuspostmaster &pg_connect("dbname=MyDbName");OKpostmaster -i &pg_connect("dbname=MyDbName");OKpostmaster &pg_connect("host=localhost dbname=MyDbName");
Unable to connect to PostgreSQL server: connectDB() failed:
Is the postmaster running and accepting TCP/IP (with -i)
connection at 'localhost' on port '5432'? in
/path/to/file.php on line 20.
postmaster -i &pg_connect("host=localhost dbname=MyDbName");OK
A connection to PostgreSQL server can be established with the
following value pairs set in the command string: $conn =
pg_connect("host=myHost port=myPort tty=myTTY options=myOptions
dbname=myDB user=myUser password=myPassword ");
The previous syntax of:
$conn = pg_connect ("host", "port", "options", "tty", "dbname")
has been deprecated.
Environmental variables affect PostgreSQL server/client
behavior. For example, PostgreSQL module will lookup PGHOST
environment variable when the hostname is omitted in the connection
string. Supported environment variables are different from version
to version. Refer to PostgreSQL Programmer's Manual (libpq -
Environment Variables) for details.
Make sure you set environment variables for appropriate user. Use
$_ENV or getenv to check
which environment variables are available to the current process.
Setting default parameters
Starting with PostgreSQL 7.1.0, you can store up to 1GB into a
field of type text. In older versions, this was limited to the block
size (default was 8KB, maximum was 32KB, defined at compile time)
To use the large object (lo) interface, it is required to enclose
large object functions within a transaction block. A transaction
block starts with a SQL statement BEGIN and if
the transaction was valid ends with COMMIT or
END. If the transaction fails the transaction
should be closed with ROLLBACK or
ABORT.
Using Large Objects
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You should not close the connection to the PostgreSQL server
before closing the large object.
&reference.pgsql.functions;