| Warning |
Use of PostgreSQL module with PHP 4.0.6 is not recommended due to
a bug in notice message handling.
|
| Warning |
PostgreSQL function names will be changed in 4.2.0 release to
confirm current coding standard. Most of new names will have
additional under score(s), e.g. pg_lo_open(). Some functions are
renamed to different name for consistency. e.g. pg_exec() to
pg_query(). Older names may be used in 4.2.0 and a few releases
from 4.2.0, but they may be deleted in the future. CVS version
has new function names.
Example 1. Function names changed OLD NAME NEW NAME
pg_exec pg_query
getlastoid pg_last_oid
pg_cmdtuples pg_affected_rows
pg_errormessage pg_last_error
pg_numrows pg_num_rows
pg_numfields pg_num_fields
pg_fieldname pg_field_name
pg_fieldsize pg_field_size
pg_fieldtype pg_field_type
pg_fieldnum pg_field_num
pg_fieldprtlen pg_field_prtlen
pg_fieldisnull pg_field_is_null
pg_freeresult pg_free_result
pg_result pg_fetch_result
pg_loreadall pg_lo_read_all
pg_locreate pg_lo_create
pg_lounlink pg_lo_unlink
pg_loopen pg_lo_open
pg_loclose pg_lo_close
pg_loread pg_lo_read
pg_lowrite pg_lo_write
pg_loimport pg_lo_import
pg_loexport pg_lo_export |
|
Obsolete pg_connect()/pg_pconnect() syntax will be depreciated to
support async connect feature in the future. Please use
connection string for pg_connect() and pg_pconnect().
|
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 www.postgresql.org.
In order to enable PostgreSQL support,
"--with-pgsql[=DIR]" 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 file which comes with source distribution.
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".
Table 1. Postmaster and PHP
| Postmaster | PHP | Status |
|---|
| postmaster & | pg_connect("dbname=MyDbName"); | OK |
| postmaster -i & | pg_connect("dbname=MyDbName"); | OK |
| postmaster & | 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 variable affects PostgreSQL server/client
behavior. For example, PostgreSQL module will lookup PGHOST
environment variable when hostname is omitted in connection
string. Supported environment variables are different from version
to version. Refer to PostgreSQL Programmer's Manual (libpq -
Environment Variables) for details.
From PostgreSQL 7.1.0, text data type has 1GB as its max
size. Older PostgreSQL's text data type is limited by block
size. (Default 8KB. Max 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.
Example 2. Using Large Objects <?php
$database = pg_connect ("dbname=jacarta");
pg_exec ($database, "begin");
$oid = pg_locreate ($database);
echo ("$oid\n");
$handle = pg_loopen ($database, $oid, "w");
echo ("$handle\n");
pg_lowrite ($handle, "large object data");
pg_loclose ($handle);
pg_exec ($database, "commit");
?> |
|
Do not close connection resource before closing large object
resource.
