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  PostgreSQL - PHP 接口

  • 安装

    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--without-pgsql在编译时。您仍然可以使用 yum 命令安装 PHP -PostgreSQL 接口 - 
    
yum install php-pgsql
    在开始使用 PHP PostgreSQL 界面之前，请先找到pg_hba.confPostgreSQL 安装目录中的文件并添加以下行 - 
    
# IPv4 local connections:
host    all         all         127.0.0.1/32          md5
    您可以使用以下命令启动/重新启动 postgres 服务器，以防它未运行 - 
    
[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。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，它们可以满足您在 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 ] )
    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，那么在第二次调用 pg_connect() 时会创建一个新连接，即使 connection_string 与现有连接相同。
    2
    bool pg_connection_reset ( resource $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
    string pg_dbname ([ resource $connection ] )
    此例程返回给定 PostgreSQL 连接资源的数据库的名称。
    5
    resource pg_prepare ([ resource $connection ], string $stmtname, string $query )
    这会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
    resource pg_execute ([ resource $connection ], string $stmtname, array $params )
    该例程发送请求以执行具有给定参数的准备好的语句并等待结果。
    7
    resource pg_query ([ resource $connection ], string $query )
    该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 ([ 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 )
    此例程转义文字以插入文本字段。
    15
    string pg_escape_string ([ resource $connection ], string $data )
    此例程转义字符串以查询数据库。

  • 连接到数据库

    以下 PHP 代码显示了如何连接到本地计算机上的现有数据库，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，让我们运行上面给出的程序来打开我们的数据库testdb：如果数据库成功打开，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);
?>
    执行上述给定程序时，它将在您的testdb它将显示以下消息 - 
    
Opened database successfully
Table created successfully

  • 插入操作

    以下 PHP 程序显示了我们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);
?>
    执行上述给定程序时，它将在 COMPANY 表中创建给定记录并显示以下两行 - 
    
Opened database successfully
Records created successfully

  • 选择操作

    以下 PHP 程序显示了我们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);
?>
    执行上述给定程序时，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

  • 更新操作

    以下 PHP 代码显示了我们如何使用 UPDATE 语句更新任何记录，然后从我们的 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);
?>
    执行上述给定程序时，它将产生以下结果 - 
    
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

  • 删除操作

    下面的 PHP 代码展示了我们如何使用 DELETE 语句删除任何记录，然后从我们的 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);
?>
    执行上述给定程序时，它将产生以下结果 - 
    
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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