Pl Sql Error Handling
In Example 10-5, you call raise_application_error if an error condition of your choosing happens (in this case, if the current schema owns less than 1000 tables): Example 10-5 Raising an Application This chapter contains these topics: Overview 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 LOGIN_DENIED 01017 -1017 A program attempts to log on to Oracle with an invalid username or password. For the message codes of all PL/SQL warnings, see Oracle Database Error Messages. http://iipseconline.com/pl-sql/pl-sql-error-handling-example.html
Exceptions also improve reliability. IF number_on_hand < 1 THEN RAISE out_of_stock; END IF; EXCEPTION WHEN out_of_stock THEN -- handle the error END; You can also raise a predefined exception explicitly. After an exception handler runs, control transfers to the next statement of the enclosing block. Instead, you must assign their values to local variables, then use the variables in the SQL statement, as shown in the following example: DECLARE err_num NUMBER; err_msg VARCHAR2(100); BEGIN ...
By associating the exception code to a name and using it as a named exception. Sometimes the error is not immediately obvious, and could not be detected until later when you perform calculations using bad data. That is, the exception reproduces itself in successive enclosing blocks until a handler is found or there are no more blocks to search. If the company has zero earnings, the division operation raises the predefined exception ZERO_DIVIDE and the executable part of the block transfers control to the exception-handling part.
In the following example, you declare an exception named past_due: DECLARE past_due EXCEPTION; Exception and variable declarations are similar. The message begins with the Oracle error code. To reraise an exception, use a RAISE statement without an exception name, which is allowed only in an exception handler: Example 10-9 Reraising a PL/SQL Exception DECLARE salary_too_high EXCEPTION; current_salary NUMBER IF ...
At the level of the SQL*Plus prompt, every update/insert/delete has one implicit savepoint, and also the invocation of any unnamed block. A cursor must be closed before it can be reopened. dbms_output.put_line('Complete Error Stack:'); FOR v_ErrorRec in c_ErrorCur LOOP dbms_output.put(' ' || v_ErrorRec.facility || '-'); dbms_output.put(TO_CHAR(v_ErrorRec.error_number) || ': '); dbms_output.put_line(v_ErrorRec.error_mesg); END LOOP; END PrintStacks; --=================================================== PROCEDURE The functions SQLCODE and SQLERRM are especially useful in the OTHERS exception handler because they tell you which internal exception was raised.
Test your code with different combinations of bad input data to see what potential errors arise. SELF_IS_fs ORA-30625 Program attempted to call a MEMBER method, but the instance of the object type has not been intialized. What does the SQLERRM Function do? DBMS_OUTPUT.PUT_LINE('Can''t handle an exception in a declaration.'); END; / Handlers in the current block cannot catch the raised exception because an exception raised in a declaration propagates immediately to the enclosing
For internal exceptions, SQLCODE returns the number of the Oracle error. https://www.tutorialspoint.com/plsql/plsql_exceptions.htm In procedural statements, VALUE_ERROR is raised if the conversion of a character string into a number fails. (In SQL statements, INVALID_NUMBER is raised.) ZERO_DIVIDE Your program attempts to divide a number Example 11-1 Setting Value of PLSQL_WARNINGS Compilation Parameter For the session, enable all warnings—highly recommended during development: ALTER SESSION SET PLSQL_WARNINGS='ENABLE:ALL'; For the session, enable PERFORMANCE warnings: ALTER SESSION SET PLSQL_WARNINGS='ENABLE:PERFORMANCE'; Thus, a block or subprogram can have only one OTHERS handler.
That way, an exception handler written for the predefined exception can process other errors, as the following example shows: DECLARE acct_type INTEGER := 7; BEGIN IF acct_type NOT IN (1, 2, news That way, you can report errors to your application and avoid returning unhandled exceptions. SUBSCRIPT_OUTSIDE_LIMIT Your program references a nested table or varray element using an index number (-1 for example) that is outside the legal range. For information about autonomous routines, see "AUTONOMOUS_TRANSACTION Pragma".
DECLARE Child_rec_exception EXCEPTION; PRAGMA EXCEPTION_INIT (Child_rec_exception, -2292); BEGIN Delete FROM product where product_id= 104; EXCEPTION WHEN Child_rec_exception THEN Dbms_output.put_line('Child records are present for this product_id.'); END; / c) User-defined Exceptions Apart For user-defined exceptions, SQLCODE returns +1 and SQLERRM returns the message: User-Defined Exception. Example 11-2 uses an ALTER SESSION statement to disable all warning messages for the session and then compiles a procedure that has unreachable code. have a peek at these guys You cannot use SQLCODE or SQLERRM directly in a SQL statement.
You cannot return to the current block from an exception handler. 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 Raised How PL/SQL Exceptions Associate the name with the error code of the internally defined exception.
A specific exception handler is more efficient than an OTHERS exception handler, because the latter must invoke a function to determine which exception it is handling.
Use error-checking code wherever bad input data can cause an error. For example, you might want to roll back a transaction in the current block, then log the error in an enclosing block. However, an exception name can appear only once in the exception-handling part of a PL/SQL block or subprogram. COMPILE statement.
Note: The language of warning and error messages depends on the NLS_LANGUAGE parameter. That is, the built-in parameter SELF (which is always the first parameter passed to a MEMBER method) is null. You can define exceptions of your own in the declarative part of any PL/SQL block, subprogram, or package. check my blog In the latter case, PL/SQL returns an unhandled exception error to the host environment.
Next, the example enables all warnings for the session by invoking DBMS_WARNING.set_warning_setting_string and displays the value of PLSQL_WARNINGS by invoking DBMS_WARNING.get_warning_setting_string. EXCEPTION WHEN NO_DATA_FOUND THEN INSERT INTO errors VALUES ('Error in statement ' || stmt); END; Copyright © 1996, 2002 Oracle Corporation. Retrieving the Error Code and Error Message: SQLCODE and SQLERRM In an exception handler, you can use the built-in functions SQLCODE and SQLERRM to find out which error occurred and to