Error Handling In Pl Sql In Oracle
Contents |
Churchill Run-time errors arise from design faults, coding mistakes, hardware failures, and many other oracle pl sql exception when others sources. Although you cannot anticipate all possible errors, you can pl sql raise exception plan to handle certain kinds of errors meaningful to your PL/SQL program. With many programming pl sql exception handling examples languages, unless you disable error checking, a run-time error such as stack overflow or division by zero stops normal processing and returns control to the operating pl sql exception when others system. With PL/SQL, a mechanism called exception handling lets you "bulletproof" your program so that it can continue operating in the presence of errors. This chapter discusses the following topics: Overview of PL/SQL Error Handling Advantages of PL/SQL Exceptions Predefined PL/SQL Exceptions Defining Your Own PL/SQL Exceptions How PL/SQL Exceptions Are
User Defined Exception In Oracle
Raised How PL/SQL Exceptions Propagate Reraising a PL/SQL Exception Handling Raised PL/SQL Exceptions Tips for Handling PL/SQL Errors Overview of PL/SQL Error Handling In PL/SQL, a warning or error condition is called an exception. Exceptions can be internally defined (by the run-time system) or user defined. Examples of internally defined exceptions include division by zero and out of memory. Some common internal exceptions have predefined names, such as ZERO_DIVIDE and STORAGE_ERROR. The other internal exceptions can be given names. You can define exceptions of your own in the declarative part of any PL/SQL block, subprogram, or package. For example, you might define an exception named insufficient_funds to flag overdrawn bank accounts. Unlike internal exceptions, user-defined exceptions must be given names. When an error occurs, an exception is raised. That is, normal execution stops and control transfers to the exception-handling part of your PL/SQL block or subprogram. Internal exceptions are raised
shot at without result. —Winston Churchill Run-time errors arise from design faults, coding mistakes, hardware failures, and many other sources. Although you cannot anticipate all possible errors, you can plan to handle
Pl Sql Exception Handling Best Practices
certain kinds of errors meaningful to your PL/SQL program. With many programming languages, unless functions for error trapping are contained in which section of a pl/sql block you disable error checking, a run-time error such as stack overflow or division by zero stops normal processing and returns exception handling in oracle interview questions control to the operating system. With PL/SQL, a mechanism called exception handling lets you "bulletproof" your program so that it can continue operating in the presence of errors. This chapter contains these topics: Overview https://docs.oracle.com/cd/B10500_01/appdev.920/a96624/07_errs.htm of PL/SQL Runtime Error Handling Advantages of PL/SQL Exceptions Summary of Predefined PL/SQL Exceptions Defining Your Own PL/SQL Exceptions How PL/SQL Exceptions Are Raised How PL/SQL Exceptions Propagate Reraising a PL/SQL Exception Handling Raised PL/SQL Exceptions Tips for Handling PL/SQL Errors Overview of PL/SQL Compile-Time Warnings Overview of PL/SQL Runtime Error Handling In PL/SQL, an error condition is called an exception. Exceptions can be internally defined (by the runtime https://docs.oracle.com/cd/B13789_01/appdev.101/b10807/07_errs.htm system) or user defined. Examples of internally defined exceptions include division by zero and out of memory. Some common internal exceptions have predefined names, such as ZERO_DIVIDE and STORAGE_ERROR. The other internal exceptions can be given names. You can define exceptions of your own in the declarative part of any PL/SQL block, subprogram, or package. For example, you might define an exception named insufficient_funds to flag overdrawn bank accounts. Unlike internal exceptions, user-defined exceptions must be given names. When an error occurs, an exception is raised. That is, normal execution stops and control transfers to the exception-handling part of your PL/SQL block or subprogram. Internal exceptions are raised implicitly (automatically) by the run-time system. User-defined exceptions must be raised explicitly by RAISE statements, which can also raise predefined exceptions. To handle raised exceptions, you write separate routines called exception handlers. After an exception handler runs, the current block stops executing and the enclosing block resumes with the next statement. If there is no enclosing block, control returns to the host environment. The following example calculates a price-to-earnings ratio for a company. If the company has zero earnings, the division operation raises the predefined exception ZERO_DIVIDE, the execution of the block is interrupted,
Basic Syntax PL/SQL - Data Types PL/SQL - Variables PL/SQL - Constants PL/SQL - Operators PL/SQL - Conditions PL/SQL http://www.tutorialspoint.com/plsql/plsql_exceptions.htm - Loops PL/SQL - Strings PL/SQL - Arrays PL/SQL - Procedures PL/SQL - Functions PL/SQL - Cursors PL/SQL - Records PL/SQL - Exceptions PL/SQL - Triggers http://psoug.org/reference/exception_handling.html PL/SQL - Packages PL/SQL - Collections PL/SQL - Transactions PL/SQL - Date & Time PL/SQL - DBMS Output PL/SQL - Object Oriented PL/SQL Useful Resources PL/SQL pl sql - Questions and Answers PL/SQL - Quick Guide PL/SQL - Useful Resources PL/SQL - Discussion Selected Reading Developer's Best Practices Questions and Answers Effective Resume Writing HR Interview Questions Computer Glossary Who is Who PL/SQL - Exceptions Advertisements Previous Page Next Page An error condition during a program execution is called pl sql exception an exception in PL/SQL. PL/SQL supports programmers to catch such conditions using EXCEPTION block in the program and an appropriate action is taken against the error condition. There are two types of exceptions: System-defined exceptions User-defined exceptions Syntax for Exception Handling The General Syntax for exception handling is as follows. Here you can list down as many as exceptions you want to handle. The default exception will be handled using WHEN others THEN: DECLARE
Functions PSOUG Forum Oracle Blogs Search the Reference Library pages: FreeOracle MagazineSubscriptionsand Oracle White Papers Oracle Exception Handling Version 11.1 General NOTE: How Oracle Does Implicit Rollbacks Before executing an INSERT, UPDATE, or DELETE statement, Oracle marks an implicit savepoint (unavailable to you). If the statement fails, Oracle rolls back to the savepoint. Normally, just the failed SQL statement is rolled back, not the whole transaction. However, if the statement raises an unhandled exception, the host environment determines what is rolled back. If you exit a stored subprogram with an unhandled exception, PL/SQL does not assign values to OUT parameters. Also, PL/SQL does not roll back database work done by the subprogram. At the level of the SQL*Plus prompt, every update/insert/delete has one implicit savepoint, and also the invocation of any unnamed block. Below that, the unnamed block itself has 'sub' savepoints - one foreach insert/update/delete statement in it, and one for each subprogram unit. And so on down the line. If an error occurs, and that error is handled at any level by the time we're back at the SQL*Plus prompt, we only rollback to the immediate savepoint at the start of the update/insert/delete that errors. Otherwise we rollback to the top-level 'virtual' savepoint currently in existence, which is my offending unnamed block. That is, a handled error is handled and so can be dealt with without rolling back all the way to the top. It is handled and the transaction proceeds. Commits define the end of a transaction (and start of a new one) - rollbacks only define the end of a transaction if they rollback to the last commit, rather than savepoint (whether explicit or implicit). I came to my 'version' from the following by no means exhaustive tests: CASE 1: I created a table a with one column, a1 number, and at the sqlplus prompt inserted a row with a1 = 1. I then ran that unnamed block I referred in an earlier post that, without an e