Parse Order and Analysis

Over the years I’ve heard and learned quite a lot about how Oracle does stuff. Some of it was logical, some just details to remember (I have a really lousy memory, but somehow, I actually remember some of the details). Not too long ago I wrote a query and got a parse error, and that lead me to write this post (and a couple more that will follow).

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Using Different Languages in Oracle – Part 1

Being in North America (the English speaking side), made me understand that many people are not aware (and don’t actually care) about character sets too much. Everything supports English, and everything works. Coming from Israel, I realized that some of the language issues we have in computerized systems are less understood in the western world. For example, we write from right to left (we are not the only ones, Arabic is the same for example), and I always get strange looks when I sign a piece of paper. Another example is the completely different letters (unlike English and most European languages), and more. But we are not the only ones, many countries must have these difficulties, so I decided to write this post.

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How does the Listener Work?

My previous post about bypassing the listener was a big success. It actually broke my daily record (the previous one was the Oracle Challenge).

Anyway, because of this success, I’ve decided to write another post on the same topic. Actually, a more basic post that explains how the listener works during a connection (which I mentioned shortly in the previous post). It is a bit long and technical, I hope you’ll enjoy it, and I would appreciate any comment. Continue reading

Bypassing the Listener

The listener is the first contact we make in order to connect to the Oracle database. Therefore, as DBAs, it is also the front-end component we can secure. There are a few ways to secure the listener, and I’ll name some later.
When hackers look for an entry point to our database, any process that listens on the network and is related to Oracle is a target. The listener, in this scenario, is the first candidate, as it is the main process that listens to network connections, but is the listener the only one?
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How are Numbers Saved in Oracle?

I’ve been asked quite a few times about the difference between number and character columns in Oracle. So I decided to write this article in order to explain how things work.

Many people, mainly those with programing background, assume that Oracle, like programming languages, contains character columns that work like STRING in programing languages, and number columns that work like INTEGER, DOUBLE and similar in programing languages. If this is the case, working with numbers in Oracle is much more efficient than text, the value has a static size of 4 or 8 bytes, the CPU works with number natively in math calculations, and therefore, number columns are better (when relevant).

However, this is not the case.

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