If you want to create a new page for developers, you should create it on the Moodle Developer Resource site.

Talk:XMLDB column types

From MoodleDocs

What is the difference between int, number and float?

Well, int are integers, no decimal point (comma in Spain), you know. :-)
About the difference between number (or decimal or numeric) and float, I really think it's more related with DB internals and how such info is stored, because from their values, they are pretty equivalents (practically, practically, the same).
Initially I was going to use only one of them (number, I think), but then I discovered we had some of the others (float) currently inside Moodle, so finally I decided to implement both of them. Some RDBMS (Oracle) lacks support for the float type, so we'll convert them to number there).
Also another possibility is to convert all those float columns (2-3 only) to number to use only that. But, in order to break the minor numbers of things I decided to keep both supported in the XMLDB Schema.
Eloy Lafuente (stronk7) 20:31, 10 August 2006 (WST)

In that case, I am strongly in favour of removing all float columns. A subtle distinction like that is just going to confuse developers, and I don't want to be confused.

Or, if necessary, have support for float in the XML format, for existing tables, but don't support created new float columns in the table editing interface.Tim Hunt 23:04, 10 August 2006 (WST)

Good idea! I'll prevent creation of new "float" fields from the XMLDB Editor. Then, in the future we'll be able to change the existing ones to the "number" type. Doing it now.
Eloy Lafuente (stronk7) 00:34, 11 August 2006 (WST)

Why are datetime columns discouraged / disallowed? Using only unix timestamps makes it very hard to do useful date math (and other datetime functions) in the DB.