Tuesday, October 19, 2021

How Do You Store Boolean Data in Db2?

Recently, I was reading an article written by Ben Brumm on using Boolean data in SQL and it got me thinking about Db2 and Boolean data. You see, if you click over to the article, you'll see that Ben talks about several popular database systems, but not Db2!

So first of all, what is Boolean data? Sometimes all you want to do is to be able to store a Yes/No, True/False, 1/0 value in a column of a Db2 table. But that can be problematic. What data type should you choose? How should you model that column? Does it matter?

Well, up until recently, Db2 did not support a Boolean data type. But I guess I should be more clear: Db2 LUW offers Boolean support, but Db2 for z/OS does not have a built-in Boolean data type.

As of V9.7, you can use a Boolean data type for local variables, global variables, parameters, or return types in compound SQL (compiled) statements. So it is really only a viable option for SQL PL. As of V11.1, you can use the Boolean data type for a column in a Db2 table.

OK, so what should you do if you do not have Boolean support in the Db2 you are currently using? In my opinion, the best approach is to use a numeric solution with 1 as TRUE and 0 as FALSE. You might want to consider using a Character column with YES/NO or TRUE/FALSE, but there are several issues with that approach. Firstly, it will likely consume more storage, secondly without a constraint on the column users might specify “YES” or “Yes” or “y” or “Y”… or other variations to mean the same thing, and finally, if English is not your first language then users may have the urge to specify “Si” or “Da” or… well, you get the idea.

A good choice for a Boolean data type could be BINARY(1) which only stores binary data, so no constraint is needed. Or you might want to specify SMALLINT with a check constraint only allowing 0 and 1 as options.

If you want to allow "Unknown" as an option, then you can make the column nullable.


So, share your experiences with us here on the blog. Tell us, have you implemented Boolean data in your Db2 tables? How did you do it? And how is it working out for you? 

Monday, October 11, 2021

What is Db2?

For regular readers of this blog the title of this particular post might seem to be a bit odd. After all, why visit the Db2Portal blog if you don't know what Db2 is, right?

Well, the purpose of this short post is to refer my regular readers to an article I wrote for TechTarget, a website that regularly posts "What Is" type of articles.

So, you guessed it, I wrote the latest, updated "What is Db2?" article for TechTarget... and I figured I'd share it with my blog readers. 

Now whenever somebody asks a high-level question about Db2, like "what is it?" or "what are the advantages and disadvantages of Db2" or even "where can I run Db2?" you now have a place to send them...

Here ---> What is Db2?