Error Handling Stored Procedure Oracle
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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 oracle stored procedure exception handling of errors meaningful to your PL/SQL program. With many programming languages, unless you disable oracle stored procedure example error checking, a run-time error such as stack overflow or division by zero stops normal processing and returns control to oracle raise application error 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 discusses the following topics: Overview error handling in stored procedure sql server 2008 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 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.
Error Handling In Stored Procedure Sql Server 2012
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. 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. Th
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 errors in ttIsql Differences in TimesTen:
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exception handing and error behavior Understanding exceptions This section provides an overview of exceptions exception handling in oracle 11g example in PL/SQL programming, covering the following topics: About exceptions Exception types About exceptions An exception is a PL/SQL error that is exception handling in oracle interview questions raised during program execution, either implicitly by TimesTen or explicitly by your program. Handle an exception by trapping it with a handler or propagating it to the calling environment. For example, if your SELECT https://docs.oracle.com/cd/B10500_01/appdev.920/a96624/07_errs.htm 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 v_lname > FROM employees > WHERE first_name = 'John'; > DBMS_OUTPUT.PUT_LINE ('Last name is :' || v_lname); > https://docs.oracle.com/cd/E11882_01/timesten.112/e21639/exceptions.htm 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 occur most often in PL/SQL code You are not required to declare these exceptions. They are predefined by TimesTen. TimesTen implicitly raises the error. Non-predefined TimesTen error Any other standard TimesTen error These must be declared in t
program to continue to operate in the presence of errors. Topics: Overview of PL/SQL Run-Time Error Handling Guidelines https://docs.oracle.com/cd/B28359_01/appdev.111/b28370/errors.htm for Avoiding and Handling PL/SQL Errors and Exceptions Advantages of PL/SQL Exceptions Predefined PL/SQL Exceptions Defining Your Own PL/SQL Exceptions How PL/SQL Exceptions Are Raised How PL/SQL http://allthingsoracle.com/error-handling/ Exceptions Propagate Reraising a PL/SQL Exception Handling Raised PL/SQL Exceptions Overview of PL/SQL Compile-Time Warnings Overview of PL/SQL Run-Time Error Handling In PL/SQL, an error condition stored procedure is called an exception. An exception can be either internally defined (by the run-time system) or user-defined. Examples of internally defined exceptions are ORA-22056 (value string is divided by zero) and ORA-27102 (out of memory). Some common internal exceptions have predefined names, such as ZERO_DIVIDE and STORAGE_ERROR. The other internal exceptions can be given oracle stored procedure names. You can define your own exceptions 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. 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 or invocations of the procedure DBMS_STANDARD.RAISE_APPLICATION_ERROR. 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. For information about managing errors when using BULK COLLECT, see Handling FORALL Exceptions (%BULK_EXCEPTIONS Attribute). Example 11-1 calculates a price-to-earnings ratio for a company. If the compan
you should consider them as your closest friends. They are the ones that honestly say what is wrong with your program. We cannot foresee all possible problematic events, and even the best programmers write bugs. Exceptions There are three kinds of exceptions Internally defined: A system error, defined by Oracle, that occurs. Predefined: The most common internally defined exceptions that are given predefined names. User defined: A logical error which you define and raise yourself System errors could occur from improper coding, like the “ORA-01001: Invalid cursor”, which you should try to fix as soon as possible in your code. And the “TOO_MANY_ROWS”-error might give you clues about bad data quality. To resolve these bugs, it is important to know where, when and why it happened. But system errors could also occur from hardware failures, like the “ORA-12541: TNS: no listener”, when an ftp-server might be unreachable over the network. In that case, all you can do, and should do, is provide proper error handling and transaction management, and give as detailed information as possible about this situation to the people that need to know. These system-errors always have an error number assigned, so you can easily identify the error. The 22 predefined exceptions also have a name assigned, which allows for easier, and more readable exception handling. For the other, non-predefined, system-errors, a name can be linked by using the pragma “EXCEPTION_INIT”. DECLARE network_error EXCEPTION; PRAGMA EXCEPTION_INIT(network_error, -12541); BEGIN ... EXCEPTION WHEN too_many_rows THEN ... WHEN network_error THEN ... END; User defined errors we will raise ourselves. They can be given a number and a name. To raise a user defined error with a chosen number and error message, we call the procedure “RAISE_APPLICATION_ERROR”. Oracle allows us the create error numbers in the range of -20000 to -20999. This allows us to create 1000 unique error codes for our logical errors throughout our application. Just like we did for system errors, we can name our user defined errors by using the pragma “EXCEPTION_INIT”. BEGIN RAISE_APPLICATION_ERROR(-20000,’Logical error occured’); END; If we do not care about the error code and error message, and we will foresee an exception block to directly handle the error, we could also raise errors by the keyword “RAISE”, followed by the exception name. If we do not handle the error, the error ORA-65000, “Unhandled user exception” is propagated. DECLARE logical_error EXCEPTION; BEGIN RAISE logical_error; EXCEPTIO