What are the essential differences between procedure and function in Oracle?

1. Different identifiers. The identifier of the FUNCTION is FUNCTION and the process is PROCEDURE.

2. In a function, variable parameters are generally not used, and function values are directly returned using the function name. If a return value exists in a process, the variable parameters must be returned.

3. The process has no type and cannot be assigned a value. If the function has a type, the function value must be transferred to the function name.

4. When defining a function, you must describe the type of the function.

5. Different call methods. Function calls appear in expressions. process calls are completed by independent process call statements.

6. A process is generally designed to obtain several computing results to complete a series of data processing or computing-independent operations. A function is often used only to obtain a function value.

Function can be used in the expression x: = func (); procedure cannot

Function can be used as the expression select func () from dual; procedure cannot

Function cannot BEGIN in func (); END; procedure can