>Go To Admin>System>Manage Datatables and click on 'Create Datatable.
>Provide any name for data table select application table name as 'Client.
> Provide column name and column type as 'String', and then click on '+' button to add.
> Then click on 'Submit' button.
>Throwing validation , 'Required Field' (check screenshot) ..It's always expecting one more column to be added