PDO::sqliteCreateCollation

Registers a User Defined Function for use as a collating function in SQL statements

Description

public bool PDO::sqliteCreateCollation ( string $name , callable $callback )

Warning

This function is EXPERIMENTAL. The behaviour of this function, its name, and surrounding documentation may change without notice in a future release of PHP. This function should be used at your own risk.

Parameters

name

Name of the SQL collating function to be created or redefined.

callback

The name of a PHP function or user-defined function to apply as a callback, defining the behavior of the collation. It should accept two strings and return as strcmp() does, i.e. it should return -1, 1, or 0 if the first string sorts before, sorts after, or is equal to the second.

This function need to be defined as:

int collation ( string $string1 , string $string2 )

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example #1 PDO::sqliteCreateCollation example


<?php
$db = new PDO('sqlite::memory:');
$db->exec("CREATE TABLE test (col1 string)");
$db->exec("INSERT INTO test VALUES ('a1')");
$db->exec("INSERT INTO test VALUES ('a10')");
$db->exec("INSERT INTO test VALUES ('a2')");

$db->sqliteCreateCollation('NATURAL_CMP', 'strnatcmp');
foreach ($db->query("SELECT col1 FROM test ORDER BY col1") as $row) {
  echo $row['col1'] . "\n";
}
echo "\n";
foreach ($db->query("SELECT col1 FROM test ORDER BY col1 COLLATE NATURAL_CMP") as $row) {
  echo $row['col1'] . "\n";
}
?>

The above example will output:

a1
a10
a2

a1
a2
a10

Notes

Note:
This method is not available with the SQLite2 driver. Use the old style sqlite API for that instead.