PHP连接及操作PostgreSQL数据库的方法详解

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:

yum install php-pgsql

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 restart Stopping 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:

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