mysql_list_dbs
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
mysql_list_fields
(PHP 4, PHP 5)
mysql_list_fields — List MySQL table fields
Описание
resource mysql_list_fields
( string $database_name
, string $table_name
[, resource $link_identifier
] )
Retrieves information about the given table name.
This function is deprecated. It is preferable to use mysql_query() to issue a SQL SHOW COLUMNS FROM table [LIKE 'name'] statement instead.
Параметри
- database_name
-
The name of the database that's being queried.
- table_name
-
The name of the table that's being queried.
- link_identifier
-
Връзката към MySQL. Ако не е указана, се използва последната създадена връзка от mysql_connect(). Ако не намери такава връзка, ще направи опит да установи връзка, все едно е изпълнена mysql_connect() без параметри. Ако случайно не е намерена или създадена никаква връзка, ще се генерира предупреждение от ниво E_WARNING.
Връщани стойности
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() и mysql_field_type().
Примери
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);
}
}
?>
Примерът по-горе ще изведе нещо подобно на:
Array
(
[Field] => id
[Type] => int(7)
[Null] =>
[Key] => PRI
[Default] =>
[Extra] => auto_increment
)
Array
(
[Field] => email
[Type] => varchar(100)
[Null] =>
[Key] =>
[Default] =>
[Extra] =>
)
Бележки
Забележка: От съображения за обратна съвместимост, може да бъде използван следният непрепоръчителен псевдоним: mysql_listfields()
Вж. също
- mysql_field_flags() - Get the flags associated with the specified field in a result
- mysql_info() - Get information about the most recent query
add a note
User Contributed Notes
mysql_list_fields
perwool at seznam dot cz
29-Oct-2007 02:32
steve at tequilasolutions dot com
12-Sep-2006 06:33
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
rhyous at yahoo dot com
04-Jun-2005 03:22
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 $row[col[firstcolumn]]. This becomes useful when you have a lot of columns.
mbevan at marginsoftware dot com
13-Nov-2003 01:40
If you're willing to use a lot of functions to get a little information about fields in a table, this function is for you. If you just want to get all the information you can find, you can use this:
<?php
// Taken from: http://ca.php.net/manual/en/function.mysql-field-flags.php
// Original by: amir at scrounch dot com
// Returns the name of the fields in the primary key for a table.
// Also keeps the fields in KEY order. Handy.
function getPrimaryKeyOf($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;
}
?>
dom at brainwaveuk dot com
19-Jul-2002 07:55
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.