PHP Unconference Europe 2015

mysql_list_fields

(PHP 4, PHP 5)

mysql_list_fieldsLista os campos de uma tabela MySQL

Descrição

resource mysql_list_fields ( string $database_name , string $table_name [, resource $link_identifier ] )

Obtém informações sobre o nome de tabela dado.

Esta função esta obsoleta. É preferrível usar mysql_query() para realizar uma consulta SQL SHOW COLUMNS FROM table [LIKE 'name'] ao invés.

Parâmetros

database_name

O nome do banco de dados que esta sendo consultado.

table_name

O nome da tabela que esta sendo consultada.

link_identifier

The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Valor Retornado

Um ponteiro de recurso resource em caso de sucesso, ou FALSE em caso de falha.

O ponteiro de resultado pode ser usado com mysql_field_flags(), mysql_field_len(), mysql_field_name() and mysql_field_type().

Exemplos

Exemplo #1 Alternativa para o obsoleto 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);
    }
}
?>

O exemplo acima irá imprimir algo similar à:

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

Notas

Nota:

Para compatibilidade com versões anteriores, o seguinte apelido obsoleto pode ser usado: mysql_listfields()

Veja Também

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User Contributed Notes 6 notes

up
0
steve at tequilasolutions dot com
8 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
up
-1
rhyous at yahoo dot com
9 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.
up
-1
mbevan at marginsoftware dot com
10 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;
}

?>
up
-2
phpflow at gmail dot com
2 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;
}
?>
up
-4
perwool at seznam dot cz
7 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
up
-3
dom at brainwaveuk dot com
12 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.
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