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。
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
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
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
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
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
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
