What is a 'stored procedure' in SQL?

A stored procedure is a precompiled named block of SQL code stored in the database. Its advantages are:  • Performance — compiled once, execution plan cached, subsequent calls are faster than parsing the same query repeatedly.  • Reduced network traffic — client sends one CALL statement instead of multiple SQL queries, only results travel back.  • Reusability — multiple applications call the same procedure (CBS, mobile banking, branch terminal all call GetCustomerLoans).  • Security — users granted EXECUTE permission on procedure without direct table access (they can't run arbitrary SELECT on the Loans table).  • Maintainability — change business logic in one place.