donia zheni wrote:
> And if it's defined with "typedef", must all operations be defined also
> in C or can some functions be defined with plpgsql?
If you want a new data type that's only accessible using functions and
operators defined to operate on it, you must write it in C.
If you wanted to use PL/PgSQL to implement some operators, you'd have to
expose innards of the data type at the SQL level. Since you explicitly
do not want to do this, you cannot use PL/PgSQL.
--
Craig Ringer