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pg_field_name

(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

pg_field_name — 返回字段名

说明

pg_field_name(PgSql\Result $result, int $field): string

pg_field_name() 返回在指定 result 实例中占据 field 字段的字段名。字段编号从 0 开始。

注意:
此函数过去称为 pg_fieldname()。

参数

result: PgSql\Result 实例，由 pg_query()、pg_query_params() 或者 pg_execute()（等）返回。
field: 字段编号，从 0 开始。

返回值

字段名。

更新日志

版本	说明
8.1.0	现在 `result` 参数接受 PgSql\Result 实例，之前接受 resource。

示例

示例 #1 获取字段信息

<?php
  $dbconn = pg_connect("dbname=publisher") or die("Could not connect");

  $res = pg_query($dbconn, "select * from authors where author = 'Orwell'");
  $i = pg_num_fields($res);
  for ($j = 0; $j < $i; $j++) {
      echo "column $j\n";
      $fieldname = pg_field_name($res, $j);
      echo "fieldname: $fieldname\n";
      echo "printed length: " . pg_field_prtlen($res, $fieldname) . " characters\n";
      echo "storage length: " . pg_field_size($res, $j) . " bytes\n";
      echo "field type: " . pg_field_type($res, $j) . " \n\n";
  }
?>

以上示例会输出：

 
column 0
fieldname: author
printed length: 6 characters
storage length: -1 bytes
field type: varchar 

column 1
fieldname: year
printed length: 4 characters
storage length: 2 bytes
field type: int2 

column 2
fieldname: title
printed length: 24 characters
storage length: -1 bytes
field type: varchar

参见

pg_field_num() - 返回名为 field 的字段编号

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User Contributed Notes 2 notes

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Anonymous ¶

19 years ago

In fact you can extract the size of the varchar field, by simply sending the following query:
"select a.atttypmod,a.attrelid from pg_attribute as a, pg_class as c where c.relname='$table' AND a.attrelid=c.oid AND a.attname='$field'"

here is a simple function that does that:

function get_field_size($table, $field, $link) {
                
        $result = pg_query($link, "select a.atttypmod,a.attrelid from pg_attribute as a, pg_class as c where c.relname='$table' AND a.attrelid=c.oid AND a.attname='$field'");                 
        
        $data = pg_fetch_object($result);
        
        return ($data->atttypmod - 4);        
    
}

returned value is a size of a given field (also varchar)

down

ccasal at compuserve dot com ¶

22 years ago

The pg_fieldname function only returns the unqualified name from the select statement. example:



select c.name, con.name from customer c, contacts con where con.customer_id = c.id;



pg_fieldname will return "name" for both fields instead of c.name and con.name.



This is a PostgreSQL limitation, not a PHP limitation.



if you need different field names you should use :



select c.name as customer_name, con.name as contact_name from customer c, contacts con where con.customer_id = c.id;



then pg_fieldname will return "customer_name" and "contact_name"

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