Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
In MySQL, how can we declare a handler while handling errors?
It is very important to handle the errors by throwing a proper error message. MySQL provides a handler to handle the error. We can declare a handler with the help of the following syntax −
Syntax of handler
DECLARE handler_action FOR condition_value statement;
The above syntax shows that we need to use DECLARE HANDLER statement to declare a handler. If a condition whose value matches the condition_value then MySQL will execute the statement and continue or exit the current code block based on the action. Followings are the three major things in the above syntax −
Handler_action is of two types and can accept one of the following values −
- CONTINUE − If the handler_action is ‘CONTINUE’ then the execution of the enclosing code block continues.
- EXIT − If the handler_action is ‘EXIT’ then the execution of the enclosing code block terminates.
Condition_value specifies a particular condition or class of conditions that activate the handler. It can accept one of the following values −
- ERROR CODE − The condition_value can be a MySQL error code.
- SQLSTATE − The condition_value can be an SQLSTATE also.
- SQLWARNING − The condition_value can be an SQLWARNING also.
- NOTFOUND − The condition_value can be a NOTFOUND also.
- SQLEXCEPTION − The condition_value can be an SQLEXCEPTION also.
The Statement can be a simple statement or compound statement enclosing by the BEGIN and END keywords.
Example
DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET got_error = 1;
In the above example, a handler means that if an error occurs then set the value of the got_error variable to 10 and continues the execution.
432 Views
