SQL: How to modify table design using SQL query?

Question

If there is away to do this and I think there is. it will help a lot.

I need to know how to add, delete modified columns in table design.
changing the Data Type, Length, Allow Nulls, Default Value.

Answer 1

Change data type

ALTER TABLE table_name

ALTER COLUMN column_name datatype





Add columns



ALTER TABLE table_name

ADD column_name datatype



Delete

ALTER TABLE table_name

DROP COLUMN column_name

Answer 2

You have 4 different things you want to store in your database: Main Category Sub Category Minute Sub Category Category So you need 4 columns. One for each. Don't try to get clever and encode the first 3 columns in a single integer field. You will go nuts trying to break the single number into the 3 components. Start with 4 columns.

Answer 3

Google for "alter table syntax".



ALTER TABLE statements are an integral part of SQL standard, just like the SELECT FROM statements.

Answer 4

That would be the MODIFY TABLE command.



I linked you in the source.

Answer 5

complex step. try searching over google. this will help!