ACL: How to Add a Computed Field

If you’ve been wondering how to add a computed field to an existing ACL table, you’re at the right place. I’ll take you through it step-by-step.

In ACL tip: What is a Computed Field?, I defined computed fields and provided 2 examples. I suggest you read that post before you dive into this one.

That post also explains expressions and functions, which you need to understand when creating computed fields. Both that post and this one are long ones, complete with graphics. You might want to print them both out first…

In this post, I’ll show you how to add the c_Region field that is described in the computed field post. It’s not as hard as it looks.

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Master List of ACL Articles and Tips

To make these posts easier to find (and link to), here’s a list of all the ACL posts on this blog in alphabetical order, and by most popular.
I’ll add other posts as they are written.

ACL tip: Quickly View/Print Table Layout

To quickly view or print the table layout in ACL, type dis in the ACL command line (dis is short for display).

The table layout contains information about the fields in a table, such as field names, field type (ASCII, Date, Numeric), field length, and most importantly, the expressions used to create computed fields. For more info on computed fields, see What is a Computed Field?

ACL tip: “Unfreezing ACL”

Occasionally when using ACL, the application appears to freeze when I open a dialog box. So I restart ACL and it works fine until I repeat the action that “froze” it in the first place. For me, it always happens when I open the Edit Layout dialog box to create a computed field. Never any other window.

Or in ACL terms, also known as “What happened to the Edit Layout screen?”

Note to non-ACL users: This problem isn’t particular to ACL, so you might want to read the “Finding the Cause” topic below before you blow off this post entirely.

I’ve noticed that this only occurs after I last used ACL on a 2-monitor system. The setup I normally use is my laptop screen plus an additional monitor.  But when I’m at home or on the road and only have my laptop, fire up ACL, and go to Edit, Layout, the problem occurs: apparent ACL freeze with every other application working.