Pl Sql Insert Error Handling
If the transaction fails, control transfers to the exception handler, where you roll back to the savepoint undoing any changes, then try to fix the problem. BEGIN * ERROR at line 1: ORA-01476: divisor is equal to zero ORA-06512: at "HR.DESCENDING_RECIPROCALS", line 19 ORA-06510: PL/SQL: unhandled user-defined exception ORA-06512: at line 2 Example 11-21 is like Example How to pass files found by find as arguments? Table 11-1 Compile-Time Warning Categories Category Description Example SEVERE Condition might cause unexpected action or wrong results. this content
You code the pragma EXCEPTION_INIT in the declarative part of a PL/SQL block, subprogram, or package using the syntax PRAGMA EXCEPTION_INIT(exception_name, -Oracle_error_number); where exception_name is the name of a previously declared For example, perhaps a table you query will have columns added or deleted, or their types changed. WHEN OTHERS THEN -- optional handler sequence_of_statements3 END; To catch raised exceptions, you write exception handlers. The following example calculates a price-to-earnings ratio for a company. https://docs.oracle.com/cd/A97630_01/appdev.920/a96624/07_errs.htm
Pl Sql Exception Handling Examples
For example, in the Oracle Precompilers environment, any database changes made by a failed SQL statement or PL/SQL block are rolled back. Handle an exception by trapping it with a handler or propagating it to the calling environment. PL/SQL predefines some common Oracle errors as exceptions. To reraise an exception, use a RAISE statement without an exception name, which is allowed only in an exception handler: DECLARE salary_too_high EXCEPTION; current_salary NUMBER := 20000; max_salary NUMBER := 10000;
In the following example, if the SELECT INTO statement raises ZERO_DIVIDE, you cannot resume with the INSERT statement: DECLARE pe_ratio NUMBER(3,1); BEGIN DELETE FROM stats WHERE symbol = 'XYZ'; SELECT price For example, you might define an exception named insufficient_funds to flag overdrawn bank accounts. The FETCH statement is expected to return no rows eventually, so when that happens, no exception is raised. Functions For Error Trapping Are Contained In Which Section Of A Pl/sql Block When the i_is_one exception handler raises ZERO_DIVIDE, the exception propagates immediately to the invoker (therefore, the ZERO_DIVIDE exception handler does not handle it).
It was very useful for my project! –SnakeSheet Jul 31 '14 at 10:49 1 This is a good practice. Add error-checking code whenever you can predict that an error might occur if your code gets bad input data. Outside an exception handler, you must specify the exception name. https://docs.oracle.com/cd/E11882_01/appdev.112/e25519/errors.htm That lets you refer to any internal exception by name and to write a specific handler for it.
If, however, you take the quiz at PL/SQL Challenge, you will be entered into a raffle to win an e-book from O’Reilly Media (oreilly.com). Exception Handling In Oracle Interview Questions In PL/SQL, the pragma EXCEPTION_INIT tells the compiler to associate an exception name with an Oracle error number. Scope Rules for PL/SQL Exceptions You cannot declare an exception twice in the same block. 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
Pl Sql Exception Handling Best Practices
You can certainly just let that exception propagate unhandled all the way out to the user, by not writing any exception sections in your subprograms. Visit Website Example 11-24 Exception Handler Runs and Execution Continues DECLARE sal_calc NUMBER(8,2); BEGIN INSERT INTO employees_temp (employee_id, salary, commission_pct) VALUES (301, 2500, 0); BEGIN SELECT (salary / commission_pct) INTO sal_calc FROM employees_temp Pl Sql Exception Handling Examples You might want to use a FOR or WHILE loop to limit the number of tries. Oracle Raise Exception With Message THEN RAISE past_due; -- this is not handled END IF; END; ------------- sub-block ends EXCEPTION WHEN past_due THEN -- does not handle RAISEd exception ...
The syntax is: PRAGMA EXCEPTION_INIT (exception_name, error_code) For semantic information, see "EXCEPTION_INIT Pragma". http://iipseconline.com/pl-sql/pl-sql-error-handling-exception.html You might want to use a FOR or WHILE loop to limit the number of tries. TimesTen error messages and SQL codes Given the same error condition, TimesTen does not guarantee that the error message returned by TimesTen is the same as the message returned by Oracle Continuing after an Exception Is Raised An exception handler lets you recover from an otherwise fatal error before exiting a block. Pl Sql Continue After Exception
So, a SELECT INTO statement that calls an aggregate function never raises NO_DATA_FOUND. That way, you can report errors to your application and avoid returning unhandled exceptions. Advantages of PL/SQL Exceptions Using exceptions for error handling has several advantages. http://iipseconline.com/pl-sql/pl-sql-error-handling-example.html 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 ...
For example, a better way to do the insert follows: INSERT INTO stats (symbol, ratio) SELECT symbol, DECODE(earnings, 0, NULL, price / earnings) FROM stocks WHERE symbol = 'XYZ'; In this Pl/sql Raises An Exception In Which Two Of The Following Cases CURSOR_ALREADY_OPENED ORA-06511 -6511 Program attempted to open an already opened cursor. Each handler consists of a WHEN clause, which specifies an exception, followed by a sequence of statements to be executed when that exception is raised.
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
In that case, we change the value that needs to be unique and continue with the next loop iteration. In Example 11-10, the procedure raises the predefined exception INVALID_NUMBER either explicitly or implicitly, and the INVALID_NUMBER exception handler always handles it. CURSOR_ALREADY_OPEN Your program attempts to open an already open cursor. How Can We Handle Errors In Pl Sql ROWTYPE_MISMATCH The host cursor variable and PL/SQL cursor variable involved in an assignment have incompatible return types.
Example 11-5 Naming Internally Defined Exception DECLARE deadlock_detected EXCEPTION; PRAGMA EXCEPTION_INIT(deadlock_detected, -60); BEGIN ... NO_DATA_FOUND A SELECT INTO statement returns no rows, or your program references a deleted element in a nested table or an uninitialized element in an index-by table. Guidelines for Avoiding and Handling Exceptions To make your programs as reliable and safe as possible: Use both error-checking code and exception handlers. check my blog So while inserting data through the scripts, whenever such an exception occurs, the script ends abruptly, and the whole transaction is rolled back.
Your session Use the ALTER SESSION statement, described in Oracle Database SQL Language Reference. SQL> drop table log_table; Table dropped. If there is no handler for the exception, then PL/SQL returns an unhandled exception error to the invoker or host environment, which determines the outcome (for more information, see "Unhandled Exceptions"). 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';
That is, the exception reproduces itself in successive enclosing blocks until either a block has a handler for it or there is no enclosing block. The number of rows of data that are imported runs into thousands, and the source data is not clean (unexpected nulls in NOT NULL columns, etc). Assume the same package specification shown there, which declares the procedures and functions hire_employee, remove_employee, and num_above_salary. Examples of internally defined exceptions include division by zero and out of memory.
Carefully consider whether each exception handler should commit the transaction, roll it back, or let it continue. For more information, see "User-Defined Exceptions". Welcome Account Sign Out Sign In/Register Help Products Solutions Downloads Store Support Training Partners About OTN Oracle Technology Network Oracle Magazine Issue Archive 2012 March 2012 Oracle Magazine Online 2016 2015 If the exception is ever raised in that block (or any sub-block), you can be sure it will be handled.
Table 4-1 Predefined exceptions Exception name Oracle Database error number SQLCODE Description ACCESS_INTO_NULL ORA-06530 -6530 Program attempted to assign values to the attributes of an uninitialized object. THEN RAISE past_due; END IF; END; ------------- sub-block ends EXCEPTION ... Once the exception has been raised, all you can do is handle the exception—or let it “escape” unhandled to the host environment. END; Omitting the exception name in a RAISE statement--allowed only in an exception handler--reraises the current exception.
Before starting the transaction, mark a savepoint. However, the same scope rules apply to variables and exceptions. END; In this example, if the SELECT INTO statement raises a ZERO_DIVIDE exception, the local handler catches it and sets pe_ratio to zero.