Function validate_unique

Validation of a record uniqueness

Package: PHPLucidFrame\Core
Copyright: Copyright (c), PHPLucidFrame.
License: MIT License This source file is subject to the MIT license that is bundled with this source code in the file LICENSE
Author: Sithu sithu@phplucidframe.com
Located at helpers/validation_helper.php

Parameters summary
`mixed`	`$value`	The value to check for uniqueness
`string`	`$table`	The table name without prefix
`string`	`$field`	The field name in the table to check
`integer`	`$id = 0`	The optional ID field to be excluded

Return value summary
`boolean`	TRUE if the value already exists in the table; otherwise FALSE