PostgreSQL database is Open Source product and
available without cost. 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.
To use PostgreSQL support, you need PostgreSQL 6.5
or later, PostgreSQL 7.0 or later to enable all
PostgreSQL module features. PostgreSQL supports many
character encoding including multibyte character
encoding. The current version and more information
about PostgreSQL is available at
http://www.postgresql.org/.
In order to enable PostgreSQL support, --with-pgsql[=DIR] is required when you
compile PHP. DIR is the PostgreSQL base install
directory, defaults to
/usr/local/pgsql. If shared object module is
available, PostgreSQL module may be loaded using
extension directive in
php.ini or dl() function.
php.ini中的設定會影響這些函數的行為。
表格 1. PostgreSQL configuration options
Here is a short explanation of the configuration
directives.
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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 do not use an older
libpq than the PostgreSQL Server to which you will be
connecting. 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".
表格 3. Postmaster and PHP
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.
以下的常數由此延伸定義, 只在這個延伸被編譯成PHP或實行時期被動態載入時有效。
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.