PHP连接PostgreSQL数据库
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 databasen";
} else {
echo "Opened database successfullyn";
}
?>
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 databasen";
} else {
echo "Opened database successfullyn";
}
$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($db);
} else {
echo "Table created successfullyn";
}
pg_close($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
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 databasen";
} else {
echo "Opened database successfullyn";
}
$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($db);
} else {
echo "Records created successfullyn";
}
pg_close($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 databasen";
} else {
echo "Opened database successfullyn";
}
$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] ."nn";
}
echo "Operation done successfullyn";
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 databasen";
} else {
echo "Opened database successfullyn";
}
$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 successfullyn";
}
$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] ."nn";
}
echo "Operation done successfullyn";
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 databasen";
} else {
echo "Opened database successfullyn";
}
$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 successfullyn";
}
$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] ."nn";
}
echo "Operation done successfullyn";
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
