Condition and Handler in action : Condition HANDLER « Procedure Function « MySQL Tutorial

Home
MySQL Tutorial
1.Introduction
2.Select Query
3.Database
4.Table
5.Table Join
6.Subquery
7.Insert Update Delete
8.Logic Operator
9.View
10.Data Types
11.Procedure Function
12.Cursor
13.Trigger
14.Date Time Functions
15.Comparison Functions Operators
16.Aggregate Functions
17.Cast Functions Operators
18.Control Flow Functions
19.Encryption Compression Functions
20.Information Functions
21.Math Numeric Functions
22.Miscellaneous Functions
23.String Functions
24.Regular Expressions
25.Data Dictionary
26.MySQL Utilities
27.Privilege
MySQL Tutorial » Procedure Function » Condition HANDLER 
11.44.2.Condition and Handler in action

By declaring conditions and handlers, you can catch certain MySQL errors or SQLSTATE conditions.

mysql>
mysql>
mysql> DELIMITER //
mysql>
mysql> CREATE FUNCTION perform_logic (some_input INT(10)) returns INT(10)
    -> BEGIN
    ->         DECLARE problem CONDITION FOR 1265;
    ->         DECLARE EXIT HANDLER FOR problem
    ->                 RETURN NULL;
    ->
    ->         # do some logic, if the problem condition is met
    ->         # the function will exit, returning a NULL
    ->
    ->         RETURN 1;
    -> END
    -> //
Query OK, rows affected (0.00 sec)

mysql> DELIMITER ;
mysql>
mysql> drop function perform_logic;
Query OK, rows affected (0.00 sec)

mysql>
11.44.Condition HANDLER
11.44.1.Declaring a Condition and Handler
11.44.2.Condition and Handler in action
11.44.3.DECLARE CONTINUE HANDLER FOR NOT FOUND SET
11.44.4.Checking flag
11.44.5.Using while to check the condition
11.44.6.DECLARE EXIT HANDLER FOR
11.44.7.Checking Exit flag
11.44.8.Using the IF statement to verify 'CONTINUE HANDLER'
11.44.9.The example associates a handler with SQLSTATE 23000, which occurs for a duplicate-key error
11.44.10.To ignore a condition
java2s.com  | Contact Us | Privacy Policy
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.