Handling Error In Pl Sql
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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 certain kinds of errors meaningful to your pl sql exception handling examples PL/SQL program. With many programming languages, unless you disable error checking, a run-time error oracle raise exception with message such as stack overflow or division by zero stops normal processing and returns control to the operating system. With PL/SQL, a mechanism oracle predefined exceptions 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 exception when others 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 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
Pl Sql Exception Handling Best Practices
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. In the example below, you calculate and store a price-to-earnings ratio for a company with ticker symbol XYZ. If the company has zero earnings, the predefined exception ZERO_DIVIDE is raised. This stops normal execution of the block and transfers control to the exception handlers. The optional OTHERS handler catches all exceptions that the block does not name specifically. DECLARE pe_rati
errors. The latter are called exceptions. Note: The language of warning and error messages depends on the NLS_LANGUAGE parameter.
Functions For Error Trapping Are Contained In Which Section Of A Pl/sql Block
For information about this parameter, see Oracle Database Globalization Support Guide. Topics oracle sqlerrm Compile-Time Warnings Overview of Exception Handling Internally Defined Exceptions Predefined Exceptions User-Defined Exceptions Redeclared Predefined Exceptions Raising Exceptions pl sql exception handling continue loop Explicitly Exception Propagation Unhandled Exceptions Error Code and Error Message Retrieval Continuing Execution After Handling Exceptions Retrying Transactions After Handling Exceptions See Also: "Exception Handling in Triggers" "Handling FORALL Exceptions https://docs.oracle.com/cd/A97630_01/appdev.920/a96624/07_errs.htm After FORALL Statement Completes" Tip: If you have problems creating or running PL/SQL code, check the Oracle Database trace files. The USER_DUMP_DEST initialization parameter specifies the current location of the trace files. You can find the value of this parameter by issuing SHOW PARAMETER USER_DUMP_DEST. For more information about trace files, see Oracle Database Performance Tuning Guide. Compile-Time Warnings https://docs.oracle.com/cd/E11882_01/appdev.112/e25519/errors.htm While compiling stored PL/SQL units, the PL/SQL compiler generates warnings for conditions that are not serious enough to cause errors and prevent compilation—for example, using a deprecated PL/SQL feature. To see warnings (and errors) generated during compilation, either query the static data dictionary view *_ERRORS (described in Oracle Database Reference) or, in the SQL*Plus environment, use the command SHOW ERRORS. The message code of a PL/SQL warning has the form PLW-nnnnn. For the message codes of all PL/SQL warnings, see Oracle Database Error Messages. Table 11-1 summarizes the categories of warnings. Table 11-1 Compile-Time Warning Categories Category Description Example SEVERE Condition might cause unexpected action or wrong results. Aliasing problems with parameters PERFORMANCE Condition might cause performance problems. Passing a VARCHAR2 value to a NUMBER column in an INSERT statement INFORMATIONAL Condition does not affect performance or correctness, but you might want to change it to make the code more maintainable. Code that can never run By setting the compilation parameter PLSQL_WARNINGS, you can: Enable and disable all warnings, one or more categories of warnings, or
Error Handling" in Oracle Database PL/SQL Language Reference. See the end of this chapter for TimesTen-specific considerations. The following topics are covered: Understanding exceptions Trapping exceptions Showing https://docs.oracle.com/cd/E11882_01/timesten.112/e21639/exceptions.htm errors in ttIsql Differences in TimesTen: exception handing and error behavior Understanding exceptions This section provides an overview of exceptions in PL/SQL programming, covering the following topics: About exceptions Exception types https://www.techonthenet.com/oracle/exceptions/sqlerrm.php About exceptions An exception is a PL/SQL error that is raised during program execution, either implicitly by TimesTen or explicitly by your program. Handle an exception by trapping it with a handler pl sql or propagating it to the calling environment. For example, if your SELECT statement returns multiple rows, TimesTen returns an error (exception) at runtime. As the following example shows, you would see TimesTen error 8507, then the associated ORA error message. (ORA messages, originally defined for Oracle Database, are similarly implemented by TimesTen.) Command> DECLARE > v_lname VARCHAR2 (15); > BEGIN > SELECT last_name INTO pl sql exception v_lname > FROM employees > WHERE first_name = 'John'; > DBMS_OUTPUT.PUT_LINE ('Last name is :' || v_lname); > END; > / 8507: ORA-01422: exact fetch returns more than requested number of rows 8507: ORA-06512: at line 4 The command failed. You can handle such exceptions in your PL/SQL block so that your program completes successfully. For example: Command> DECLARE > v_lname VARCHAR2 (15); > BEGIN > SELECT last_name INTO v_lname > FROM employees > WHERE first_name = 'John'; > DBMS_OUTPUT.PUT_LINE ('Last name is :' || v_lname); > EXCEPTION > WHEN TOO_MANY_ROWS THEN > DBMS_OUTPUT.PUT_LINE (' Your SELECT statement retrieved multiple > rows. Consider using a cursor.'); > END; > / Your SELECT statement retrieved multiple rows. Consider using a cursor. PL/SQL procedure successfully completed. Exception types There are three types of exceptions: Predefined exceptions are error conditions that are defined by PL/SQL. Non-predefined exceptions include any standard TimesTen errors. User-defined exceptions are exceptions specific to your application. In TimesTen, these three types of exceptions are used in the same way as in Oracle Database. Exception Description How to handle Predefined TimesTen error One of approximately 20 errors that
Server MySQL MariaDB PostgreSQL SQLite MS Office Excel Access Word Web Development HTML CSS Color Picker Languages C Language More ASCII Table Linux UNIX Java Clipart Techie Humor Advertisement Oracle Basics Oracle Advanced Oracle Cursors Oracle Exception Handling Named Programmer-Defined Exception Named System Exception WHEN OTHERS Clause SQLCODE SQLERRM Oracle Foreign Keys Oracle Loops/Conditionals Oracle Transactions Oracle Triggers String/Char Functions Numeric/Math Functions Date/Time Functions Conversion Functions Analytic Functions Advanced Functions NEXT: Declare Cursor Oracle / PLSQL: SQLERRM Function This Oracle tutorial explains how to use the Oracle/PLSQL SQLERRM function with syntax and examples. What does the SQLERRM Function do? The SQLERRM function returns the error message associated with the most recently raised error exception. This function should only be used within the Exception Handling section of your code. Syntax The syntax for the SQLERRM function in Oracle/PLSQL is: SQLERRM Parameters or Arguments There are no parameters or arguments for the SQLERRM function. Note See also the SQLCODE function. Example Since EXCEPTION HANDLING is usually written with the following syntax: EXCEPTION WHEN exception_name1 THEN [statements] WHEN exception_name2 THEN [statements] WHEN exception_name_n THEN [statements] WHEN OTHERS THEN [statements] END [procedure_name]; You could use the SQLERRM function to raise an error as follows: EXCEPTION WHEN OTHERS THEN raise_application_error(-20001,'An error was encountered - '||SQLCODE||' -ERROR- '||SQLERRM); END; Or you could log the error to a table using the SQLERRM function as follows: EXCEPTION WHEN OTHERS THEN err_code := SQLCODE; err_msg := SUBSTR(SQLERRM, 1, 200); INSERT INTO audit_table (error_number, error_message) VALUES (err_code, err_msg); END; NEXT: Declare Cursor Share this page: Advertisement Back to top Home | About Us | Contact Us | Testimonials | Donate While using this site, you agree to have read and accepted our Terms of Service and Privacy Policy. We use advertisements to support this website and fund the development of new content. Copyright © 2003-2016 TechOnTheNet.com. All rights reserved.