"Christopher Kings-Lynne" <[EMAIL PROTECTED]> writes: >> There might be other cases of legal direct change of system catalog >> entries, e,g. varchar to text, if they all are only names for internally >> identical data structures. Can you tell which datatypes may be legally >> interchanged?
> Yes, you can check if they're binary compatible from the pg_cast table.... But nearly all of the interesting cases require you to understand the type's interpretation of typmod, and you can't learn that from a table. How many cases are there where blindly looking for a binary-compatible cast in pg_cast will really do you much good? AFAICS you'd have to set atttypmod to -1 if you change atttypid without knowing very specifically what you are changing from and to. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]