constraint for a column only

[Katja Fink]

Dear all,

When designing a database it would be so helpful to avoid false data being typed in the database table. Sometimes a constraint helps to make sure to write into one table first before in another.

Now I was looking for something that I would call colument constraint - which I thought I could find a solution by creating a trigger. Aim is to make sure that no nonsense data - for example for dates would be not accepted by "apply changes" when a date is greater than f.e. sysdate.

Or is there a way to get a description message ... ???

Again I am lucky if someone has an idea - or the mySQL developer team understands the problem I have ...

Greetings from Germany, Cathy