public function validate_unique($value, $input, $args)
    {
        $table  = $args[0];
        $column = $args[1];
        $value  = trim($value);

        $exists = $this->db->prepare("
            SELECT count(*) as count
            FROM {$table}
            WHERE {$column} = :value
        ");

        $exists->execute([
            'value' => $value
        ]);

        return ! (bool) $exists->fetchObject()->count;
    }
public function validate_unique($value, $input, $args)
    {
        $table  = $args[0];
        $column = $args[1];
        $value  = trim($value);

        $exists = $this->db->prepare("
            SELECT count(*) as count
            FROM {$table}
            WHERE {$column} = :value
        ");

        $exists->execute([
            'value' => $value
        ]);

        return ! (bool) $exists->fetchObject()->count;
    }
public function validate_unique ( $ value , $ input , $ args ) { $ table = $ args [ 0 ] ; $ column = $ args [ 1 ] ; $ value = trim ( $ value ) ; $ exists = $ this -> db -> prepare ( "
            SELECT count(*) as count
            FROM {$table}
            WHERE {$column} = :value
        " ) ; $ exists -> execute ( [ 'value' => $ value ] ) ; return ! ( bool ) $ exists -> fetchObject ( ) -> count ; }
Check if a value already exists in a database table.

@param  mixed $value
@param  array $input
@param  array $args

@return bool
Check if a value already exists in a database table .