Newbie Question: Command for only Y or N in a column.

Question

I am just starting on SQL developer and need to know how to enter the command to change a table so that it will only accept a Y or N in the column. I know this is exceedingly simple but how do do it appears nowhere in my textbook.
Thank you!

Answer 1

Hi,
Welcome to the forum!
What you need is a Check Constraint , like this:
CREATE TABLE     table_x
     complete_flag     VARCHAR2 (1)     
               CONSTRAINT x_complete_flag_chk
               CHECK     ( complete_flag     IN ('Y', 'N')
);For details, look up "Check constraints" in the SQL Language manual:
http://download.oracle.com/docs/cd/B28359_01/server.111/b28286/clauses002.htm#sthref3031
This question actually doesn''t have anything to do with SQL Developer or SQL*Plus, which are front-end tools for communicating with the database. In the future, you'll be better off posting questions like this in the SQL and PL/SQL forum:
PL/SQL
I know it's not easy to tell them apart when you're just beginning. When in doubt, it's probably best to guess that it's a SQL question, and post it in the forum above.