mysql_list_fields

(PHP 4, PHP 5)

mysql_list_fields — List MySQL table fields

Avviso

This function was deprecated in PHP 5.4.0, and it and the entire original MySQL extension was removed in PHP 7.0.0. Instead, use either the actively developed MySQLi or PDO_MySQL extensions. See also the MySQL: choosing an API guide. Alternatives to this function include:

SQL Query: SHOW COLUMNS FROM sometable

Descrizione

mysql_list_fields(string $database_name, string $table_name, resource $link_identifier = NULL): resource

Retrieves information about the given table name.

This function is deprecated. It is preferable to use mysql_query() to issue an SQL SHOW COLUMNS FROM table [LIKE 'name'] statement instead.

Elenco dei parametri

database_name: The name of the database that's being queried.
table_name: The name of the table that's being queried.
link_identifier: La connessione MySQL. Se l'identificativo di connessione non è specificato, l'ultima connessione aperta da mysql_connect() viene assunta. Se questa connessione non è trovata, si cercherà di crearne una come se mysql_connect() fosse stata chiamata senza argomenti. Se una connessione non è trovata oppure non viene stabilita, un avviso di livello E_WARNING viene generato.

Valori restituiti

A result pointer resource on success, or false on failure.

The returned result can be used with mysql_field_flags(), mysql_field_len(), mysql_field_name() e mysql_field_type().

Esempi

Example #1 Alternate to deprecated mysql_list_fields()

<?php
$result = mysql_query("SHOW COLUMNS FROM sometable");
if (!$result) {
    echo 'Could not run query: ' . mysql_error();
    exit;
}
if (mysql_num_rows($result) > 0) {
    while ($row = mysql_fetch_assoc($result)) {
        print_r($row);
    }
}
?>

Il precedente esempio visualizzerà qualcosa simile a:

Array
(
    [Field] => id
    [Type] => int(7)
    [Null] =>  
    [Key] => PRI
    [Default] =>
    [Extra] => auto_increment
)
Array
(
    [Field] => email
    [Type] => varchar(100)
    [Null] =>
    [Key] =>
    [Default] =>
    [Extra] =>
)

Note

Nota:
Per la compatibilità all'indietro, i seguenti sinonimi (deprecati) possono essere utilizzati: mysql_listfields()

Vedere anche:

mysql_field_flags() - Get the flags associated with the specified field in a result
mysql_info() - Get information about the most recent query

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User Contributed Notes 7 notes

down

mbevan at marginsoftware dot com ¶

21 years ago


If you're willing to use a lot of functions to get a little information about fields in a table, this function is for you.  If you just want to get all the information you can find, you can use this:

<?php

// Taken from: http://ca.php.net/manual/en/function.mysql-field-flags.php
// Original by: amir at scrounch dot com
// Returns the name of the fields in the primary key for a table.
// Also keeps the fields in KEY order.  Handy.
function getPrimaryKeyOf($table) { 
  $keys = Array();

  $query = sprintf("SHOW KEYS FROM `%s`", $table);
  $result = mysql_query($query) or die(mysql_error());

  while ($row = mysql_fetch_assoc($result)) {
    if ( $row['Key_name'] == 'PRIMARY' )
      $keys[$row['Seq_in_index'] - 1] = $row['Column_name'];
  }

  return $keys;
}

// Returns a bunch of information about a table...
// The name of the auto-increment field, if any, fields in the
// primary key (using the function above), and all information
// about all fields.
function getTableInformationOf($table) {
  $information = array(
      "auto"    => "",
      "primary" => array(),
      "fields"  => array()
    );

  $information['primary'] = $this->getPrimaryKeyOf($table);

  $result = mysql_query("DESC `$table`");
  while ( $field = mysql_fetch_assoc($result) ) {
    $information['fields'][] = $field;
    if ( $field['Extra'] == "auto_increment" )
      $information['auto'] = $field['Field'];
  }

  return $information;
}

?>

down

rhyous at yahoo dot com ¶

19 years ago


To make an array containing the names of a column from a table, you use the following simple script: (Note: using table1 with three columns)



<?php

$qColumnNames = mysql_query("SHOW COLUMNS FROM table1",$db) or die("mysql error");

$numColumns = mysql_num_rows($qColumnNames);

$x = 0;

while ($x < $numColumns)

{

    $colname = mysql_fetch_row($qColumnNames);

    $col[$colname[0]] = $colname[0];

    $x++;

}



print_r($col);



/* it will have the following output

Array (

[firstcolumn] => firstcolumn

[secondcolumn] => secondcolumn

[thirdcolumn] => thirdcolumn

)

*/

?>



Or you can number the columns from zero.  This help when using it in conjunction with mysql_fetch_row to get an array.  You don't have to remember which number of the array a certain column is.



<?php

$qColumnNames = mysql_query("SHOW COLUMNS FROM table1",$db) or die("mysql error");

$numColumns = mysql_num_rows($qColumnNames);

$x = 0;

while ($x < $numColumns)

{

    $colname = mysql_fetch_row($qColumnNames);

    $col[$colname[0]] = $x;

    $x++;

}



print_r($col);



/* it will have the following output

Array (

[firstcolumn] => 0

[secondcolumn] => 1

[thirdcolumn] => 2

)

*/

?>



To use it in conjuction with mysql_fetch_row:



<?php

$row = mysql_fetch_row("SELECT * from table1",$db) or die("mysql error");

?>



You can now call $row[col[firstcolumn]].  This becomes useful when you have a lot of columns.

down

-3

phpflow at gmail dot com ¶

12 years ago


Below script is used to get all coloumn indormation of an table.When we are working custome ORM then we need to match the coloumn name with array keys.



<?php

function getColoumn($table) {

     $result = mysql_query("SHOW COLUMNS FROM ". $table);

      if (!$result) {

        echo 'Could not run query: ' . mysql_error();

      }

      $fieldnames=array();

      if (mysql_num_rows($result) > 0) {

        while ($row = mysql_fetch_assoc($result)) {

          $fieldnames[] = $row['Field'];

        }

      }



      return $fieldnames;

}

?>

down

-6

dom at brainwaveuk dot com ¶

22 years ago


mysql_list_fields() retrieves information about the given table name but you can use something like mysql_fetch_field to retrieve the field names from a result source.

down

-8

perwool at seznam dot cz ¶

17 years ago


Every my html table output begins with heading row containing the field names. For that purpose I accepted the short combination of MySQL function, giving me a result similar to the mysql_fetch_array() for the row of values. The following example shows the basic idea. It should be adapted for the specific use:

<?php 
//...
$field_names = array_keys( mysql_fetch_array( mysql_query( $query, $link), MYSQL_ASSOC)); 
//...
?>

The advantage of this is, that it gives the names of the result, neither the field names of the whole table. 
Please read the discussion about duplicate field names in SQL result carefully. The use, as shown in the example above, increments the pointer, hence some regular function, which does not, could be more useful :-) 

Jan

down

-13

steve at tequilasolutions dot com ¶

18 years ago


Note, using mysql_list_fields will change the currently selected database so subsequent mysql_query operations will be on the database in param 1 not the one selected with mysql_select_db

down

-29

user1337 at 1337example dot com ¶

7 years ago


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