PostgreSQL - PHP 接口

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安装

在最新版本的 PHP 5.3.x 中，PostgreSQL 扩展默认启用。可以通过在编译时使用 **--without-pgsql** 来禁用它。您仍然可以使用 yum 命令来安装 PHP -PostgreSQL 接口 -

yum install php-pgsql

在开始使用 PHP PostgreSQL 接口之前，请在 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

如果 postgres 服务器未运行，您可以使用以下命令启动/重启它 -

[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 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，可以满足您从 PHP 程序中使用 PostgreSQL 数据库的要求。如果您正在寻找更复杂的应用程序，那么您可以查看 PHP 官方文档。

序号 API & 描述
1

resource pg_connect ( string $connection_string [, int $connect_type ] )

此函数打开到由 connection_string 指定的 PostgreSQL 数据库的连接。

如果将 PGSQL_CONNECT_FORCE_NEW 作为 connect_type 传递，则即使 connection_string 与现有连接相同，在第二次调用 pg_connect() 时也会创建一个新连接。
2

bool pg_connection_reset ( resource $connection )

此例程重置连接。它对错误恢复很有用。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

string pg_dbname ([ resource $connection ] )

此例程返回给定 PostgreSQL 连接资源的数据库名称。
5

resource pg_prepare ([ resource $connection ], string $stmtname, string $query )

此函数提交创建具有给定参数的预处理语句的请求并等待完成。
6

resource pg_execute ([ resource $connection ], string $stmtname, array $params )

此例程发送执行具有给定参数的预处理语句的请求并等待结果。
7

resource pg_query ([ resource $connection ], string $query )

此例程在指定的数据库连接上执行查询。
8

array pg_fetch_row ( resource $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

array pg_fetch_all ( resource $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 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 ([ resource $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

string pg_last_error ([ resource $connection ] )

此例程返回给定连接的最后一条错误消息。
14

string pg_escape_literal ([ resource $connection ], string $data )

此例程转义要插入文本字段的文字。
15

string pg_escape_string ([ resource $connection ], string $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，让我们运行上面给出的程序来打开我们的数据库 **testdb**：如果数据库成功打开，则会显示以下消息 -

Opened database successfully

创建表

以下 PHP 程序将用于在先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);
?>

执行上面给出的程序时，它将在您的 **testdb** 中创建 COMPANY 表，并显示以下消息 -

Opened database successfully
Table created successfully

INSERT 操作

以下 PHP 程序显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);
?>

执行上面给出的程序时，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);
?>

执行上面给出的程序时，将产生以下结果。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

UPDATE 操作

以下 PHP 代码显示了如何使用 UPDATE 语句更新任何记录，然后从我们的 COMPANY 表中获取和显示更新后的记录 -

<?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);
?>

执行上面给出的程序时，将产生以下结果 -

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

以下 PHP 代码显示了如何使用 DELETE 语句删除任何记录，然后从我们的 COMPANY 表中获取和显示剩余的记录 -

<?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);
?>

执行上面给出的程序时，将产生以下结果 -

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
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