pg_field_size()

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

返回指定字段占用内部存储空间的大小

说明

pg_field_size(resource $result,int $field_number): int

pg_field_size()返回 PostgreSQL$result中指定字段占用内部存储空间的大小（字节数）。字段编号从 0 开始。字段大小为-1 表示可变长度字段。如果出错本函数返回FALSE。

参考pg_field_name()页面中的例子。

Note:

本函数以前的名字为pg_fieldsize()。

参见pg_field_prtlen()和pg_field_type()。

To view the file structure of a table using a sql query
select pg_class.relname, pg_attribute.attname, pg_type.typname, pg_type.typlen from pg_class, pg_attribute, pg_type where pg_class.relname = 'YOURTABLENAME' and pg_class.oid = pg_attribute.attrelid and pg_type.oid = pg_attribute.atttypid having attnum > 0

function get_create_syntax( $table )
{
 $qry = "
      SELECT  *
      FROM   $table
      LIMIT   1
     ";
 $res = pg_query( $qry );
 $row = pg_fetch_assoc( $res );
 $create = "CREATE TABLE $table \n(\n";
 $item = array();
 for( $i = 0; $i < count( $row ); $i++ )
 {
  $name = pg_field_name( $res, $i );
  $type = pg_field_type( $res, $i );
  $size = pg_field_size( $res, $i );
  $item[$i] = '"'.$name.'" '.$type;
  $qry = "
       SELECT  a.atttypmod  AS size,
            a.attnotnull AS notnull
       FROM   pg_attribute AS a,
            pg_class   AS c
       WHERE   c.relname  = '$table'
       AND    a.attrelid = c.oid
       AND    a.attname  = '$name'
       ";
  $res2 = pg_query( $qry );
  $out = pg_fetch_object( $res2 );
  if( $out -> size != -1 )
  {
   $item[$i] .= '('.( $out -> size - 4 ).')';
  }
  if( $out -> notnull == 't' )
  $item[$i] .= ' NOT';
  $item[$i] .= ' NULL';
 }
 $create .= implode( ",\n", $item ) ."\n);";
 return $create;
}

How i can extract the struct of a Postgresql Table?
I want to do a dynamic php code, that see the pg table, and print name, type and size of fields