How to allow only one row for a table?

Question

I have one table in which I would like only one entry. So if someone is trying to insert another row it shouldn\'t be allowed, only after someone deleted the pr

Answer 1

Add a new column to the table, then add a check constraint and a uniqueness constraint on this column. For example:

CREATE TABLE logging (
    LogId integer UNIQUE default(1),
    MyData text,
    OtherStuff numeric,
    Constraint CHK_Logging_singlerow CHECK (LogId = 1)
);

Now you can only ever have one row with a LogId = 1. If you try to add a new row it will either break the uniqueness or check constraint.

(I might have messed up the syntax, but it gives you an idea?)