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Welcome to Datavail’s Blog, where you can read the latest insights, tips and opinions of our experts on all things data and technology.


Q+A: Nulls and DASD

Let’s say I have a table A which has 500 columns. Out of those 500 columns only 5 columns have been defined as not nullable and the rest have been defined as NULLS allowed.

Craig Mullins | December 14, 2015

VARCHAR versus Compression

This blog will compare the use of VARCHAR to DB2 compression when you are building your DB2 databases. Visit to learn more.

Craig Mullins | October 27, 2015

Evaluating DB2 Tool Vendors

You should really do the investigative work required to find out the real level of support for DB2 V11 that is in the GA version of the tool. Read more.

Craig Mullins | September 1, 2015

Adding Column Names to an Unload File

Are any of the DB2 unload utilities able to include the column names in the same file as the unload output data? Read on to discover the answer.

Craig Mullins | August 19, 2015

Advice on Using Variable Character Columns in DB2

One of the long-standing, troubling questions in DB2-land is when to use VARCHAR versus CHAR.

Craig Mullins | August 4, 2015

Returning Only Numeric Data

We want to examine CHAR data but return only those where the entire data consists only of numbers. For example, can we write a query like this?

Craig Mullins | May 26, 2015

How and When to Use DB2 Scrollable Cursors

If you are using DB2 V7 or higher, consider using scrollable cursors. With scrollable cursors, you can move directly to the rows you want without having to FETCH every other row returned by the cursor.

Craig Mullins | May 19, 2015

Using Nulls in DB2

If a column “value” can be null, it can mean one of two things: the attribute is not applicable for certain occurrences of the entity, or the attribute applies to all entity occurrences, but the information may not always be known.

Craig Mullins | April 6, 2015


DSNTEP2 is an application program that can be used to issue DB2 dynamic SQL statements.

Craig Mullins | February 19, 2015