本文实例讲述了PHP连接及操作PostgreSQL数据库的方法。分享给大家供大家参考，具体如下：
PostgreSQL扩展在默认情况下在最新版本的PHP 5.3.x中是启用的。 可以在编译时使用--without-pgsql来禁用它。仍然可以使用yum命令来安装PHP-PostgreSQL接口：
在开始使用PHP连接PostgreSQL接口之前，请先在PostgreSQL安装目录中找到pg_hba.conf文件，并添加以下行：
# IPv4 local connections:host all all 127.0.0.1/32 md5
您可以启动/重新启动postgres服务器，使用以下命令运行：
[root@host]# service postgresql restartStopping postgresql service: [ OK ]Starting postgresql service: [ OK ]
Windows用户必须启用php_pgsql.dll才能使用此扩展名。这个DLL包含在最新版本的PHP 5.3.x中的Windows发行版中。
PHP连接到PostgreSQL数据库
以下PHP代码显示如何连接到本地机器上的现有数据库，最后将返回数据库连接对象。
<?php $host = "host=127.0.0.1"; $port = "port=5432"; $dbname = "dbname=testdb"; $credentials = "user=postgres password=pass123"; $db = pg_connect( "$host $port $dbname $credentials" ); if(!$db){ echo "Error : Unable to open database/n"; } else { echo "Opened database successfully/n"; }?> 现在，让我们运行上面的程序打开数据库:testdb，如果成功打开数据库连接，那么它将给出以下消息：
Opened database successfully
创建表
以下PHP程序将用于在之前创建的数据库(testdb)中创建一个表：
<?php $host = "host=127.0.0.1"; $port = "port=5432"; $dbname = "dbname=testdb"; $credentials = "user=postgres password=pass123"; $db = pg_connect( "$host $port $dbname $credentials" ); if(!$db){ echo "Error : Unable to open database/n"; } else { echo "Opened database successfully/n"; } $sql =<<<EOF CREATE TABLE COMPANY (ID INT PRIMARY KEY NOT NULL, NAME TEXT NOT NULL, AGE INT NOT NULL, ADDRESS CHAR(50), SALARY REAL);EOF; $ret = pg_query($db, $sql); if(!$ret){ echo pg_last_error($db); } else { echo "Table created successfully/n"; } pg_close($db);?> 当执行上述程序时，它将在testdb数据库中创建COMPANY表，并显示以下消息：
Opened database successfully
Table created successfully
SQL
插入操作
以下PHP程序显示了如何在上述示例中创建的COMPANY表中创建记录：
<?php $host = "host=127.0.0.1"; $port = "port=5432"; $dbname = "dbname=testdb"; $credentials = "user=postgres password=pass123"; $db = pg_connect( "$host $port $dbname $credentials" ); if(!$db){ echo "Error : Unable to open database/n"; } else { echo "Opened database successfully/n"; } $sql =<<<EOF INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) VALUES (1, 'Paul', 32, 'California', 20000.00 ); INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) VALUES (2, 'Allen', 25, 'Texas', 15000.00 ); INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) VALUES (3, 'Teddy', 23, 'Norway', 20000.00 ); INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) VALUES (4, 'Mark', 25, 'Rich-Mond ', 65000.00 );EOF; $ret = pg_query($db, $sql); if(!$ret){ echo pg_last_error($db); } else { echo "Records created successfully/n"; } pg_close($db);?> 当执行上述程序时，它将在COMPANY表中创建给定的记录，并显示以下两行：
Opened database successfully
Records created successfully
SELECT操作
以下PHP程序显示了如何从上述示例中创建的COMPANY表中获取和显示记录：
<?php $host = "host=127.0.0.1"; $port = "port=5432"; $dbname = "dbname=testdb"; $credentials = "user=postgres password=pass123"; $db = pg_connect( "$host $port $dbname $credentials" ); if(!$db){ echo "Error : Unable to open database/n"; } else { echo "Opened database successfully/n"; } $sql =<<<EOF SELECT * from COMPANY;EOF; $ret = pg_query($db, $sql); if(!$ret){ echo pg_last_error($db); exit; } while($row = pg_fetch_row($ret)){ echo "ID = ". $row[0] . "/n"; echo "NAME = ". $row[1] ."/n"; echo "ADDRESS = ". $row[2] ."/n"; echo "SALARY = ".$row[4] ."/n/n"; } echo "Operation done successfully/n"; pg_close($db);?> 当执行上述程序时，将产生以下结果。 请记下，在创建表时按照它们使用的顺序返回字段。
Opened database successfully
ID = 1
NAME = Paul
ADDRESS = California
SALARY = 20000
ID = 2
NAME = Allen
ADDRESS = Texas
SALARY = 15000
ID = 3
NAME = Teddy
ADDRESS = Norway
SALARY = 20000
ID = 4
NAME = Mark
ADDRESS = Rich-Mond
SALARY = 65000
Operation done successfully
更新操作
以下PHP代码显示了如何使用UPDATE语句来更新指定记录，然后从COMPANY表中获取并显示更新的记录：
<?php $host = "host=127.0.0.1"; $port = "port=5432"; $dbname = "dbname=testdb"; $credentials = "user=postgres password=pass123"; $db = pg_connect( "$host $port $dbname $credentials" ); if(!$db){ echo "Error : Unable to open database/n"; } else { echo "Opened database successfully/n"; } $sql =<<<EOF UPDATE COMPANY set SALARY = 25000.00 where ID=1;EOF; $ret = pg_query($db, $sql); if(!$ret){ echo pg_last_error($db); exit; } else { echo "Record updated successfully/n"; } $sql =<<<EOF SELECT * from COMPANY;EOF; $ret = pg_query($db, $sql); if(!$ret){ echo pg_last_error($db); exit; } while($row = pg_fetch_row($ret)){ echo "ID = ". $row[0] . "/n"; echo "NAME = ". $row[1] ."/n"; echo "ADDRESS = ". $row[2] ."/n"; echo "SALARY = ".$row[4] ."/n/n"; } echo "Operation done successfully/n"; pg_close($db);?> 执行上述程序时，会产生以下结果：
Opened database successfully
Record updated successfully
ID = 2
NAME = Allen
ADDRESS = 25
SALARY = 15000
ID = 3
NAME = Teddy
ADDRESS = 23
SALARY = 20000
ID = 4
NAME = Mark
ADDRESS = 25
SALARY = 65000
ID = 1
NAME = Paul
ADDRESS = 32
SALARY = 25000
Operation done successfully
删除操作
以下PHP代码显示了如何使用DELETE语句删除指定记录，然后从COMPANY表中获取并显示剩余的记录：
<?php $host = "host=127.0.0.1"; $port = "port=5432"; $dbname = "dbname=testdb"; $credentials = "user=postgres password=pass123"; $db = pg_connect( "$host $port $dbname $credentials" ); if(!$db){ echo "Error : Unable to open database/n"; } else { echo "Opened database successfully/n"; } $sql =<<<EOF DELETE from COMPANY where ID=2;EOF; $ret = pg_query($db, $sql); if(!$ret){ echo pg_last_error($db); exit; } else { echo "Record deleted successfully/n"; } $sql =<<<EOF SELECT * from COMPANY;EOF; $ret = pg_query($db, $sql); if(!$ret){ echo pg_last_error($db); exit; } while($row = pg_fetch_row($ret)){ echo "ID = ". $row[0] . "/n"; echo "NAME = ". $row[1] ."/n"; echo "ADDRESS = ". $row[2] ."/n"; echo "SALARY = ".$row[4] ."/n/n"; } echo "Operation done successfully/n"; pg_close($db);?> 执行上述程序时，会产生以下结果：
Opened database successfully
Record deleted successfully
ID = 3
NAME = Teddy
ADDRESS = 23
SALARY = 20000
ID = 4
NAME = Mark
ADDRESS = 25
SALARY = 65000
ID = 1
NAME = Paul
ADDRESS = 32
SALARY = 25000
Operation done successfully
希望本文所述对大家PHP程序设计有所帮助。
注：相关教程知识阅读请移步到PHP教程频道。
