Question

Is there any bad affect if I use TEXT data-type to store an ID number in a database?
I do something like:

CREATE TABLE GenData ( EmpName TEXT NOT NULL, ID TEXT PRIMARY KEY);

And actually, if I want to store a date value I usually use TEXT data-type. If this is a wrong way, what is its disadvantage?

I am using PostgreSQL.

Answer 1

Storing numbers in a text column is a very bad idea. You lose a lot of advantages when you do that:

• you can’t prevent storing invalid numbers (e.g. ‘foo’)
• Sorting will not work the way you want to (’10’ is “smaller” than ‘2’)
• it confuses everybody looking at your data model.

I want to store a date value I usually use TEXT

That is another very bad idea. Mainly because of the same reasons you shouldn’t be storing a number in a text column. In addition to completely wrong dates (‘foo’) you can’t prevent “invalid” dates either (e.g. February, 31st). And then there is the sorting thing, and the comparison with > and <, and the date arithmetic….