One of the probably most unnerving things in databases is dealing with NULLs, especially when comparing data. The necessary logic to deal with NULLs can lead to very verbose code – but if you’re using Oracle, there is a very neat function you can use.
Wrapping some functionality into a nice little PL/SQL package can make your life so much easier.
I demonstrate this with a small utility-package to deal with Version-Strings.
SQLcl is a great tool, but it has its problems when it comes to environments other than English/US.
I show a couple of Problems and Strangenesses here and give examples how to work around them.
Ever tried to sort Version-Strings with pure SQL – for example when you want to find the highest Flyway version installed in your database?
Let me show you how you can!
My previous solution to split a string into rows by a delimiter, using pure SQL had a couple of small flaws.
Here is the revisited version that also removes a bit of code duplication.
Steven Feuerstein will do some live refactoring in his “Feuertips” episode #13.
However, in order to confidently refactor, one could use some automated tests that ensure the functionality doesn’t change…
Sometimes we have data that is not split into columns and rows, but SQL can only really thrive on structured data.
But thanks to recursive queries we can split any string into rows – with pure SQL.
It is a common practice to eliminate possible NULL values from your method’s parameters, and in the past I advocated to use subtypes to do this in PL/SQL.
However, it doesn’t work from SQL…