PostgreSQL连接PHP

安装

Postgresql的扩展是默认启用的最新版本的PHP5.3.x.但是它可能通过在编译时加上--without-pgsql选项禁用。但仍然可以使用yum命令安装PHP的Postgresql的接口：

yum install PHP-pgsql

在开始使用PHP Postgresql接口，打开pg_hba.conf文件(在Postgresql安装目录)，并添加下面一行：

# IPv4 local connections:
host    all         all         127.0.0.1/32          md5

使用start/restart启动Postgres服务器，它没有运行使用下面的命令：

[root@host]# service postgresql restart
Stopping postgresql service:                               [  OK  ]
Starting postgresql service:                               [  OK  ] yiibai.com

Windows用户必须启用PHP_pgsql.dll为了使用这个扩展。这个DLL包含带Windows分布在最新版本PHP5.3.x

有关详细的安装说明，请查看我们的PHP教程和其官方网站上。www.yiibai.com

PHP 接口APIs

以下是重要的PHP程序，可以连接使用Postgresql 数据库 PHP程序。如果正在寻找一个更复杂的应用程序，那么可以看看到PHP官方文件。www.yiibai.com

S.N.	API & 描述
1	resource pg_connect ( string $connection_string [,int $connect_type ] )www.yiibai.com 这将打开一个连接到Postgresql 数据库由connection_string指定。如果PGsql_CONNECT_FORCE_NEW会传递为connect_type，然后在第二个调用的情况下，对pg_connect（）创建一个新的连接，即使connection_string一个现有的连接是相同的。
2	bool pg_connection_reset ( resource $connection ) 此例程重置连接。它是有用的错误恢复。成功返回TRUE或失败则返回FALSE。
3	int pg_connection_status ( resource $connection ) 这个例程返回指定的连接状态。返回PGsql_CONNECTION_OK或PGsql_CONNECTION_BAD。
4	string pg_dbname ([ resource $connection ] ) 这个例程返回给定的Postgresql 数据库连接资源的名称。
5	resource pg_prepare ([ resource $connection ],string $stmtname,string $query ) 提交请求以创建具有给定参数的准备好的语句，并等待完成。
6	resource pg_execute ([ resource $connection ],array $params ) 这个程序发送一个请求给定的参数执行准备好的语句，并等待结果。
7	resource pg_query ([ resource $connection ],string $query ) 此程序执行查询指定的数据库连接。
8	array pg_fetch_row ( resource $result [,int $row ] ) 该例程将指定的结果的资源相关联的，数据从结果中获取一个行。www.yiibai.com
9	array pg_fetch_all ( resource $result ) 这个例程返回一个数组，包含所有行（记录），结果资源。
10	int pg_affected_rows ( resource $result ) 这个例程返回INSERT，UPDATE和DELETE查询受到影响的行数。
11	int pg_num_rows ( resource $result ) 这个例程返回的行数，例如SELECT语句返回的行数在一个Postgresql结果资源。
12	bool pg_close ([ resource $connection ] ) 该例程关闭非持久连接到一个给定的连接资源相关的Postgresql 数据库。
13	string pg_last_error ([ resource $connection ] ) 这个例程返回的最后一个错误消息，对于一个给定的连接。
14	string pg_escape_literal ([ resource $connection ],string $data ) 此例程转义文字插入一个文本字段。
15	string pg_escape_string ([ resource $connection ],string $data ) 这例程转义一个字符串查询数据库。www.yiibai.com

连接到数据库

下面的PHP 代码显示了如何连接到一个现有的在本地机器上的数据库，最后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的程序来打开数据库testdb，如果成功打开数据库，然后它会给下面的消息：

Opened database successfully

创建表

下面的PHP程序将使用以前创建的数据库中创建一个表：

<?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);
?>

上述程序执行时，它会创建表COMPANY在数据库testdb中，它会显示以下消息：

Opened database successfully
Table created successfully

INSERT操作

PHP程序，显示我们如何创建表COMPANY在上面的例子中，创建表中的记录：www.yiibai.com

<?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,SALARY)
      VALUES (2,'Allen',25,'Texas',15000.00 );

      INSERT INTO COMPANY (ID,SALARY)
      VALUES (3,'Teddy',23,'Norway',SALARY)
      VALUES (4,'Mark','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);
?> www.yiibai.com

上述程序执行时，它会创建COMPANY表中的记录，并会显示以下两行：

Opened database successfully
Records created successfully
 www.yiibai.com

SELECT 操作

PHP程序表明我们如何获取并显示COMPANY在上面的例子中创建表的记录：

<?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
      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);
?>

当上述程序执行时，它会产生以下结果。字段返回序列中，它们被用来创建表的同时保持注意。

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

UPDATE 操作

下面的PHP 代码显示了如何我们可以使用UPDATE语句来更新任何记录，然后获取并显示更新的记录，从COMPANY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
      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);
?>

当上述程序执行时，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

DELETE 操作

下面的PHP 代码，表明我们如何能够使用DELETE语句删除任何记录，然后获取并显示COMPANY表剩余的记录：

<?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);
?>