SQL/PSM

SQL/PSM, short for SQL/Persistent Stored Modules, is an ISO standard that mainly defines an extension of SQL with a procedural language for use in stored procedures. It was first published in 1996 as an extension of SQL-92, as ISO/IEC 9075-4:1996, and was later folded into the multi-part SQL:1999 standard, where it has been part 4 ever since, most recently in SQL:2023. The SQL statements for defining, managing and invoking routines moved into part 2, SQL/Foundation, so that only the procedural language itself remains in SQL/PSM. It standardizes the syntax and meaning of control flow, condition handling, local variables, assignment to variables and parameters, and procedural use of cursors, and it defines an information schema for stored procedures. Its facilities are optional in the SQL standard. The language is derived, apparently directly, from Oracle PL/SQL, which was itself based on Ada; IBM SQL PL and Mimer SQL were the first two products officially implementing it, and several other database procedural languages follow it closely without being fully compatible.