The LIKE operator is a very useful one. It is used to match strings with partial match while using the underscore (‘_’) as a single character wildcard and the percentage sign (‘%’) as multiple character wildcard.
Remember my post about Oracle 12.2 release date? I’ve heard rumors that Oracle changed the date to March 1st, and it was right!
Oracle 12.2 is available for download for Linux x86-64, and Solaris (both SPARC and x86-64). I don’t know the release dates for other platforms. This is the download page: http://www.oracle.com/technetwork/database/enterprise-edition/downloads/index.html
I’m downloading it as I write, and hopefully will have time to play with it a little bit soon. I wrote so much about new features that I have to try some of them at least. Stay tuned!
When writing a query with order by, we can use the column position instead of its name. This order by”trick” is easy to use, but should be handled carefully as it affects the order of rows if the column list changes.
The internet is full of information about indexes, and for a reason. Indexes in a database is probably the most important performance related topic. There are so many cases, properties, and different ways to use indexes that there is simply a lot to write about. In this post I’d like to talk about a specific use case that I’ve seen a few times, and is related to index scans and performance.
When user A creates a procedure and grants execute permissions to user B, user B can execute the procedure (obviously), but he can also see the code (in ALL_SOURCE view).
Databases are designed to hold data and retrieve it, so they are optimized to run queries. Over the years I’ve seen quite a few cases where the developers did things on the application side that could be easily done on the database side, and almost every time moving it to the database improved the performance. And I’m not talking about the business logic or the “application layer”, but the data access, which is the thing that the database is build for.