The Procedure Body
From InterBase
Go Up to Creating Procedures
Everything following the AS keyword in the CREATE PROCEDURE
statement forms the procedure body. The body consists of an optional list of local variable declarations followed by a block of statements.
A block is composed of statements in the InterBase procedure and trigger language, bracketed by BEGIN
and END
. A block can itself include other blocks, so that there can be many levels of nesting.
InterBase procedure and trigger language includes all standard InterBase SQL statements except data definition and transaction statements, plus statements unique to procedure and trigger language.
Features of InterBase procedure and trigger language include:
- Assignment statements, to set values of local variables and input/output parameters.
SELECT
statements, to retrieve column values.SELECT
statements must have anINTO
clause as the last clause.- Control-flow statements, such as
FOR SELECT … DO
,IF … THEN
, andWHILE … DO
, to perform conditional or looping tasks. EXECUTE PROCEDURE
statements, to invoke other procedures. Recursion is allowed.- Comments to annotate procedure code.
- Exception statements, to return error messages to applications, and
WHEN
statements to handle specific error conditions. SUSPEND
andEXIT
statements, that return control—and return values of output parameters—to the calling application.
Topics
- BEGIN … END statements
- Using Variables
- Using Assignment Statements
- Using SELECT Statements
- Using FOR SELECT … DO Statements
- Using WHILE … DO Statements
- Using IF … THEN … ELSE Statements
- Using Event Alerters
- Adding Comments
- Creating Nested and Recursive Procedures
- Using SUSPEND, EXIT, and END With Procedures