PostgreSQL PHP 接口
PostgreSQL 扩展在最新版本的 PHP 5.3.x 中默认启用。可以通过使用禁用它 --没有-pgsql 在编译时。仍然可以使用 yum 命令安装 PHP -PostgreSQL 界面：
yum install php-pgsql
在开始使用 PHP PostgreSQL 界面之前，请找到 pg_hba.conf 在 PostgreSQL 安装目录中的文件中添加以下行：
# IPv4 local connections: host all all 127.0.0.1/32 md5
你可以启动/重启 postgres 服务器，如果它没有运行，请使用以下命令：
[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。此 DLL 包含在最新版本的 PHP 5.3.x 中的 Windows 发行版中
有关详细的安装说明，请查看我们的 PHP 教程及其官方网站。
PHP 接口 API
以下是重要的 PHP 例程，它们可以满足你从 PHP 程序使用 PostgreSQL 数据库的要求。如果你正在寻找更复杂的应用程序，那么你可以查看 PHP 官方文档。
| 序号 | API & 描述 |
|---|---|
| 1 |
资源 pg_connect ( string $connection_string [, int $connect_type ] ) 这将打开到由 connection_string 指定的 PostgreSQL 数据库的连接。 如果 PGSQL_CONNECT_FORCE_NEW 作为 connect_type 传递，则在第二次调用 pg_connect() 的情况下会创建一个新连接，即使 connection_string 与现有连接相同。 |
| 2 |
bool pg_connection_reset ( 资源 $connection ) 此例程重置连接。它对于错误恢复很有用。成功时返回 TRUE，失败时返回 FALSE。 |
| 3 |
int pg_connection_status ( resource $connection ) 此例程返回指定连接的状态。返回 PGSQL_CONNECTION_OK 或 PGSQL_CONNECTION_BAD。 |
| 4 |
字符串 pg_dbname ([ 资源 $connection ] ) 此例程返回给定 PostgreSQL 连接资源的数据库名称。 |
| 5 |
资源 pg_prepare ([ 资源 $connection ], 字符串 $stmtname, 字符串 $query ) 这将提交一个请求，以使用给定的参数创建一个准备好的语句并等待完成。 |
| 6 |
资源 pg_execute ([ 资源 $connection ], 字符串 $stmtname, 数组 $params ) 此例程发送请求以执行带有给定参数的准备好的语句并等待结果。 |
| 7 |
资源 pg_query ([ 资源 $connection ], 字符串 $query ) 此例程在指定的数据库连接上执行查询。 |
| 8 |
数组 pg_fetch_row ( 资源 $result [, int $row ] ) 此例程从与指定结果资源关联的结果中获取一行数据。 |
| 9 |
数组 pg_fetch_all ( 资源 $result ) 此例程返回一个数组，其中包含结果资源中的所有行(记录)。 |
| 10 |
int pg_affected_rows ( resource $result ) 此例程返回受 INSERT、UPDATE 和 DELETE 查询影响的行数。 |
| 11 |
int pg_num_rows ( resource $result ) 此例程返回 PostgreSQL 结果资源中的行数，例如 SELECT 语句返回的行数。 |
| 12 |
bool pg_close ([ 资源 $connection ] ) 此例程关闭与给定连接资源关联的 PostgreSQL 数据库的非持久连接。 |
| 13 |
字符串 pg_last_error ([ 资源 $connection ] ) 此例程返回给定连接的最后一条错误消息。 |
| 14 |
字符串 pg_escape_literal ([ 资源 $connection ]，字符串 $data ) 此例程转义文本以插入文本字段。 |
| 15 |
字符串 pg_escape_string ([ 资源 $connection ], 字符串 $data ) 此例程转义用于查询数据库的字符串。 |
连接到数据库
以下 PHP 代码展示了如何连接到本地机器上的现有数据库，最终将返回一个数据库连接对象。
<?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，让我们运行上面给出的程序来打开我们的数据库 testdb : 如果数据库打开成功，会提示如下信息：
Opened database successfully
创建表
以下 PHP 程序将用于在之前创建的数据库中创建表：
<?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);
?>
当上面给出的程序被执行时，它会在你的目录中创建 COMPANY 表 testdb 它将显示以下消息：
Opened database successfully Table created successfully
插入操作
以下 PHP 程序展示了如何在上面示例中创建的 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);
?>
当上面给定的程序执行时，它会在 COMPANY 表中创建给定的记录，并会显示以下两行：
Opened database successfully Records created successfully
选择操作
以下 PHP 程序展示了如何从上面示例中创建的 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);
?>
当上面给出的程序被执行时，它会产生下面的结果。请注意，字段按创建表时使用的顺序返回。
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 代码展示了如何使用 UPDATE 语句更新任何记录，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);
?>
当上面给出的程序被执行时，它会产生以下结果：
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 代码展示了如何使用 DELETE 语句删除任何记录，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);
?>
当上面给出的程序被执行时，它会产生以下结果：
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