I’ve been using a query which utilizes both DBA_FREE_SPACE and DBA_DATA_FILES system views, but it often tends to be slow. Recently I’d come across another system view which is lightning fast – DBA_TABLESPACE_USAGE_METRICS. Czytaj dalej
Back in the days, when I was just beginning working as an Oracle developer, I used to view Oracle Database Server as such a great piece of software to the extent where I wouldn’t even consider that a problem which I’ve just encountered wasn’t my fault, but Oracle’s bug!
Why am I bringing this up, you might ask? Well, a few weeks ago I’ve stumbled upon a weird bug in Oracle. I was using Oracle 11.2.0.1.0. Take a look at the below example: Czytaj dalej
Once upon a time… I needed to check in the source of which objects a particular character string was included.
LONG (the pun!…) story short, non of the {USER|ALL|DBA}_SOURCE views give you a chance to search in the source of the views.
„Well, why is that a problem?!” – I hear you saying – „Don’t you know the {USER|ALL|DBA}_VIEWS views views (wait, one views too many)?”
O my, but of course! There’s a column named TEXT in them with the source of the views! Let’s try that: Czytaj dalej
The GET_DDL function of the DBMS_METADATA package, supplied by Oracle, is a nice tool to extract the DDLs of database objects. This quick guide will show you how to deal with the problem of exporting referential constraints – what problem, I hear you saying? Czytaj dalej
Hello again! It’s due time to provide the answers for my second quiz – the one about NULL in aggregate functions.
In this particular quiz, it wasn’t the point to pick the correct choices, but rather figure out what will be the result of running each of the SELECTs. Czytaj dalej
Aww. So dusty in here. Where have I been for the past seven months?!
Either way, it’s that time. Yep, you know what I mean – it’s the QUIZ TIME!
I’ve got a new quiz for you today:
What will be the result of running each of the SELECTs? Czytaj dalej
Just a quick tip for today. Oracle allows us to create special kind of indexes on columns containing long texts. One of them is the CONTEXT type. You don’t need any particular privileges to create an index of this type (other than being able to create indexes in you schema). At least, that’s what the documentation says.
There was a question about creating a CONTEXT index on StackOverflow:
I bet my cup of raspberry-juiced black tea that, somewhere along your journey with Oracle, you had to write a query which was supposed to return only the top-n rows from an ordered set. Unlike some of the other databases, MySQL, for instance, Oracle does not provide a dedicated solution to this problem.
At least, not before the 12c hit the stage.
Before I introduce you to the nice Row Limiting Clause, let me show you why the first solution that comes to mind to solve the problem at hand, in Oracle’s versions prior to 12c, is not the right one, and what voodoo tricks one has to perform to achieve the expected result. Czytaj dalej