How to create custom DB & Form for a core block?

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I know how to create custom view and controller.

Now I want to add some columns in the DB table for custom pageList (To store number of columns and other design classes)
<field name="numberOfcols" type="smallint">
      <unsigned/>
      <notnull/>
    </field>
</table>

Also after i adding this "numberOfcols" i want to add "label " in the form" to handle this value.

For future updated I dont want to change the core block or add block type (edit db.xml *--> go to dashboard "block types" --> "refersh" block). Their is other option?

siton