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Pl Sql Error Handler
Example 11-4 Locator Variables for Statements that Share Exception Handler CREATE OR REPLACE PROCEDURE loc_var AUTHID DEFINER IS stmt_no POSITIVE; name_ VARCHAR2(100); BEGIN stmt_no := 1; SELECT table_name INTO name_ FROM That way, you can report errors to your application and avoid returning unhandled exceptions. Error-handling code is scattered throughout the program. pe_ratio := stock_price / net_earnings; dbms_output.put_line('Price/earnings ratio = ' || pe_ratio); EXCEPTION -- exception handlers begin -- Only one of the WHEN blocks is executed.
Figure7-1, Figure7-2, and Figure7-3 illustrate the basic propagation rules. That is, the exception reproduces itself in successive enclosing blocks until a handler is found or there are no more blocks to search. Figure 10-1, Figure 10-2, and Figure 10-3 illustrate the basic propagation rules. All Rights Reserved. see this
Pl Sql Exception Handling Examples
Learn the names and causes of the predefined exceptions. STORAGE_ERROR ORA-06500 A hardware problem: Either RAM or disk drive. Exceptions cannot propagate across remote subprogram calls done through database links. With some better error checking, we could have avoided the exception entirely, by substituting a null for the answer if the denominator was zero: DECLARE stock_price NUMBER := 9.73; net_earnings NUMBER
Alternatively, you can use the pragma EXCEPTION_INIT to associate exception names with Oracle error codes. However, the same scope rules apply to variables and exceptions. That is, normal execution stops and control transfers to the exception-handling part of your PL/SQL block or subprogram. Pl/sql Raises An Exception In Which Two Of The Following Cases unless you used the pragma EXCEPTION_INIT to associate the exception name with an Oracle error number, in which case SQLCODE returns that error number and SQLERRM returns the corresponding error message.
The message begins with the Oracle error code. Errors are especially likely during arithmetic calculations, string manipulation, and database operations. Internal exceptions are raised implicitly (automatically) by the run-time system. https://docs.oracle.com/cd/E11882_01/appdev.112/e25519/errors.htm WHEN OTHERS THEN -- optional handler sequence_of_statements3 END; To catch raised exceptions, you write exception handlers.
Defining Your Own PL/SQL Exceptions PL/SQL lets you define exceptions of your own. User Defined Exception In Pl Sql If you know that your database operations might raise specific internally defined exceptions that do not have names, then give them names so that you can write exception handlers specifically for Example 11-21 Exception Raised in Exception Handler is Handled by Enclosing Block CREATE PROCEDURE descending_reciprocals (n INTEGER) AUTHID DEFINER IS i INTEGER; i_is_one EXCEPTION; BEGIN BEGIN i := n; LOOP IF For example, the following declaration raises an exception because the constant credit_limit cannot store numbers larger than 999: DECLARE credit_limit CONSTANT NUMBER(3) := 5000; -- raises an exception BEGIN NULL; EXCEPTION
Pl Sql Exception Handling Best Practices
So, only an OTHERS handler can catch the exception. https://docs.oracle.com/cd/E11882_01/timesten.112/e21639/exceptions.htm NOT_LOGGED_ON Your program issues a database call without being connected to Oracle. Pl Sql Exception Handling Examples However, an exception name can appear only once in the exception-handling part of a PL/SQL block or subprogram. Functions For Error Trapping Are Contained In Which Section Of A Pl/sql Block PL/SQL warning messages use the prefix PLW.
Figure 11-1 Exception Does Not Propagate Description of "Figure 11-1 Exception Does Not Propagate" In Figure 11-2, the inner block raises exception B. We use advertisements to support this website and fund the development of new content. Because the exception propagates immediately to the host environment, the exception handler does not handle it. All Rights Reserved. Pl Sql Continue After Exception
That is, normal execution stops and control transfers to the exception-handling part of your PL/SQL block or subprogram. ALTER PROCEDURE hello COMPILE PLSQL_WARNINGS='ENABLE:PERFORMANCE'; -- Recompile with extra checking. You can use the pragma EXCEPTION_INIT to associate exception names with other Oracle Database error codes that you can anticipate. Steps to be followed to use unnamed system exceptions are • They are raised implicitly. • If they are not handled in WHEN Others they must be handled explicity. • To
So, the sub-block cannot reference the global exception unless it was declared in a labeled block, in which case the following syntax is valid: block_label.exception_name The following example illustrates the scope Exception Handling In Oracle Interview Questions The latter are called exceptions. With many programming 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 system.
INVALID_NUMBER 01722 -1722 It is raised when the conversion of a character string into a number fails because the string does not represent a valid number.
You can write handlers for predefined exceptions using the names in the following list: Exception Oracle Error SQLCODE Value ACCESS_INTO_NULL ORA-06530 -6530 CASE_NOT_FOUND ORA-06592 -6592 COLLECTION_IS_NULL ORA-06531 -6531 CURSOR_ALREADY_OPEN ORA-06511 -6511 An internally defined exception always has an error code, but does not have a name unless PL/SQL gives it one or you give it one. Therefore, the values of explicit cursor attributes are not available in the handler. How Can We Handle Errors In Pl Sql If you specify TRUE, PL/SQL puts error_code on top of the error stack.
Example 4-2 Using RAISE statement to trap user-defined exception In this example, the department number 500 does not exist, so no rows are updated in the departments table. Usenet source: Ken Quirici (c.d.o.server - 29-Oct-2004) Basic Exception Handling With Error Basic Block Structure Handling CREATE OR REPLACE PROCEDURE IS BEGIN NULL; EXCEPTION WHEN THEN Since there is no customer with ID value 8 in our database, the program raises the run-time exception NO_DATA_FOUND, which is captured in EXCEPTION block. For example, when your program selects a column value into a character variable, if the value is longer than the declared length of the variable, PL/SQL stops the assignment and raises
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 SUBSCRIPT_BEYOND_COUNT Your program references a nested table or varray element using an index number larger than the number of elements in the collection. Example 11-9 Declaring, Raising, and Handling User-Defined Exception CREATE PROCEDURE account_status ( due_date DATE, today DATE ) AUTHID DEFINER IS past_due EXCEPTION; -- declare exception BEGIN IF due_date < today THEN Add exception handlers wherever errors can occur.
Summary of Predefined PL/SQL Exceptions An internal exception is raised automatically if your PL/SQL program violates an Oracle rule or exceeds a system-dependent limit. If you recompile the subprogram with a CREATE OR REPLACE statement, the current settings for that session are used. Consider the following example: BEGIN ... Example 11-19 Exception Raised in Exception Handler is Handled by Enclosing Block CREATE PROCEDURE print_reciprocal (n NUMBER) AUTHID DEFINER IS BEGIN BEGIN DBMS_OUTPUT.PUT_LINE(1/n); EXCEPTION WHEN ZERO_DIVIDE THEN DBMS_OUTPUT.PUT_LINE('Error in inner block:');
WHEN OTHERS THEN ROLLBACK; END; Because the block in which exception past_due was declared has no handler for it, the exception propagates to the enclosing block. Consider the following example: BEGIN DECLARE ---------- sub-block begins past_due EXCEPTION; due_date DATE := trunc(SYSDATE) - 1; todays_date DATE := trunc(SYSDATE); BEGIN IF due_date < todays_date THEN RAISE past_due; END IF; 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. However, when an exception is raised inside a cursor FOR loop, the cursor is closed implicitly before the handler is invoked.
SELF_IS_NULL ORA-30625 -30625 Program attempted to invoke a MEMBER method, but the object was not initialized. For example, PL/SQL raises the predefined exception NO_DATA_FOUND if a SELECT INTO statement returns no rows. Raising Exceptions Explicitly To raise an exception explicitly, use either the RAISE statement or RAISE_APPLICATION_ERROR procedure. Example 11-3 Scope of PL/SQL Exceptions DECLARE past_due EXCEPTION; acct_num NUMBER; BEGIN DECLARE ---------- sub-block begins past_due EXCEPTION; -- this declaration prevails acct_num NUMBER; due_date DATE := SYSDATE - 1; todays_date
For example, when an open host cursor variable is passed to a stored subprogram, the return types of the actual and formal parameters must be compatible. You can pass an error number to SQLERRM, in which case SQLERRM returns the message associated with that error number. So, the sub-block cannot reference the global exception unless it was declared in a labeled block, in which case the following syntax is valid: block_label.exception_name The following example illustrates the scope In the exception-handling part, you can include exception handlers for both specific and unknown errors.
You can avoid such problems by declaring individual variables with %TYPE qualifiers, and declaring records to hold query results with %ROWTYPE qualifiers. The runtime system raises them implicitly (automatically). Topics: Declaring PL/SQL Exceptions Scope Rules for PL/SQL Exceptions Associating a PL/SQL Exception with a Number (EXCEPTION_INIT Pragma) Defining Your Own Error Messages (RAISE_APPLICATION_ERROR Procedure) Redeclaring Predefined Exceptions Declaring PL/SQL Exceptions WHEN others THEN exception3-handling-statements END; Example Let us write some simple code to illustrate the concept.