Peter>I am familiar with the Java {call} escape. But I think it's pretty
Peter>useless. You're not going to get any compatibility with anything from
Peter>it, since every SQL implementation does something different with it
Would you please be more specific?
{ call ... } converts the SQL to the database-specific way of calling a stored procedure or whatever.
For instance, in Oracle DB one can have both procedures and functions.
{ ? := call my_fun() } is converted to something like begin :b0 := my_fun(); end;
{ call my_proc(?) } is converted to begin my_proc(:b0); end;
Then comes PostgreSQL, and says: you can't invoke functions/procedures like {call my_proc()}.
This not fun at all.
Note: it is not a speculation, but I have participated in extending OracleDB-kind-of-app to PostgreSQL, and {call ...} was used there for a good reason.
{call ...} are used in lots of places exactly for the reason to call procedures.
You don't need to correct application core, and one just needs to install the procedure/function at the database side,
then it should just work.
However, current state of PostgreSQL 11 blocks use of database-independent API.
Peter>If you want to call
Peter>a procedure (created with CREATE PROCEDURE), just invoke CALL directly
Peter>without any escape syntax.
That would truly surprise end users, and it would make application portability a pain.
Vladimir