(PHP 4, PHP 5, PHP 7)
pg_pconnect — 打开一个持久的 PostgreSQL 连接
$connection_string
[, int $connect_type
] )pg_pconnect() 打开一个到 PostgreSQL 数据库的持久连接。返回其它 PostgreSQL 函数所需要的连接资源号。
If a second call is made to pg_pconnect() with
the same connection_string as an existing connection, the
existing connection will be returned unless you pass
PGSQL_CONNECT_FORCE_NEW as
connect_type.
要打开持久连接功能，php.ini 中的 pgsql.allow_persistent 参数必须为 "On"（也是默认值）。 最大持久连接数目由 php.ini 中的 pgsql.max_persistent 参数定义（默认为 -1 表示没有限制）。所有连接的数目可由 php.ini 中的 pgsql.max_links 参数设置。
pg_close() 不能关闭由 pg_pconnect() 打开的持久连接。
connection_string
The connection_string can be empty to use all default parameters, or it
can contain one or more parameter settings separated by whitespace.
Each parameter setting is in the form keyword = value. Spaces around
the equal sign are optional. To write an empty value or a value
containing spaces, surround it with single quotes, e.g., keyword =
'a value'. Single quotes and backslashes within the value must be
escaped with a backslash, i.e., \' and \.
The currently recognized parameter keywords are:
host, hostaddr, port,
dbname, user,
password, connect_timeout,
options, tty (ignored), sslmode,
requiressl (deprecated in favor of sslmode), and
service. Which of these arguments exist depends
on your PostgreSQL version.
connect_type
If PGSQL_CONNECT_FORCE_NEW is passed, then a new connection
is created, even if the connection_string is identical to
an existing connection.
PostgreSQL connection resource on success, FALSE on failure.
Example #1 Using pg_pconnect()
<?php
$dbconn = pg_pconnect("dbname=mary");
//connect to a database named "mary"
$dbconn2 = pg_pconnect("host=localhost port=5432 dbname=mary");
// connect to a database named "mary" on "localhost" at port "5432"
$dbconn3 = pg_pconnect("host=sheep port=5432 dbname=mary user=lamb password=foo");
//connect to a database named "mary" on the host "sheep" with a username and password
$conn_string = "host=sheep port=5432 dbname=test user=lamb password=bar";
$dbconn4 = pg_pconnect($conn_string);
//connect to a database named "test" on the host "sheep" with a username and password
?>