![Prepared By JAVATECH “Search us in The World”
9
See Exmple…..
RAISE_APPLICATION_ERROR
Is there any technique without define exception block we can specify our
user defined error message with our own error no. Yes there is technique
called RAISE_APPLICATION_ERROR(erro_no,err_message)
Error_no range should be -20,000 to -20,999 [ give the - minus symbol ]
Message upto 2048 byte long
Where to specify it. You will write in begin section directly with errno and
err message. Generally it is defined in your user defined exception. After use](https://image.slidesharecdn.com/exceptionhandlinginplsql-180401101309/85/Exception-handling-in-plsql-9-320.jpg)
Exception handling in plsql
- 1. Prepared By JAVATECH “Search us in The World” 1 EXCEPTION HANDLING IN PLSQL What is exception ? Exceptions are abnormal condition that can be occur during the execution of program. Exceptions are used to handled run-time errors in PLSQL. And to handled that exception PLSQL specified exception block is called Exception Block. E.g.
- 2. Prepared By JAVATECH “Search us in The World” 2 Exceptions are two types 1. System Defined Exception 2. User Defined Exception System Defined Exception System Defined Exceptions are defined by Oracle Server. This exceptions contains some predefined error numbers with predefined error messages. These numbers and messages are SYSTEM_EXCEPTION ERROR_NO DESCRIPTION NO_DATA_FOUND ORA-01403 QUERY RETURN NO DATA INVALID_CURSOR ORA-01001 ILLEGAL CURSOR OPERATION OCCURRED IN PROGRAM CURSOR_ALREADY_OPEN ORA-06511 TRY TO OPEN “ALREADY OPENED CURSOR” INVALID_NUMBER ORA-01722 FAILED TO CONVERT FROM CHARACTER TO NUMBER ZERO_DIVIDE ORA-01476 ATTEMT TO DIVIDE BY ZERO (ARITHMETICEXCEPTION IN JAVA) Prepared By JAVATECH “Search us in The World” User defined Exception This exception is defined by user. You declare identifier with exception datatype. And it will de declare in declare section. And raised it inside the begin block. And if exception generated then control will automatically transferred to exception block. And exception message will displayed. There are some exception which are generated in our program but system is not defined. To control that exception we use user defined exceptions
- 3. Prepared By JAVATECH “Search us in The World” 3 EXCEPTION STRUCTURE Above diagram In User Defined Exception we use Raise keyword to send exception to specified identifier. Description 1. Declare part is used to declare variable, Exception Variable & Constants. 2. My_Exec is a variable which is defined Exception type. When exception will generate then My_Exce part will be executed. In java we write class My_Exec extends Exception to create user defined exception. 3. Between begin & Exception part your exception will be generate. So if you think exception may be occur then use raise keyword and give the exception variable name. Just I wrote Raise My_Exec. 4. Define that exception with error message. You will write
- 4. Prepared By JAVATECH “Search us in The World” 4 when My_Exec then dbms_output.put_line(‘Your own error message’); end; Now I will first show you one by one system defined exception then I will go to user defined exception. My_Table name STD99; NO_DATA_FOUND Exception Wap in PLSQL to display the row whose roll no is 9. Means roll 9 doesn’t exist then here NO_DATA_FOUND exception will generate.
- 5. Prepared By JAVATECH “Search us in The World” 5 INVALID_CURSOR Exception program It is occurred in three conditions. Actually rules of cursor is 1. Declare 2. Open 3. Fetch 4. Close When it will be invalid_cursor (If you perform invalid cursor operation) If fetch before opening cursor (I have done in my example. I first fetch then open cursor. It is wrong. Without open cursor how you will fetch first.) You closed cursor before open You fetched cursor after closing cursor.
- 6. Prepared By JAVATECH “Search us in The World” 6 CURSOR_ALREADY_OPENED Exception program. It is generated if you try to open cursor which is previously already opened. INVALID_NUMBER in java it is called NumberFormatException. It is generated when you try to insert string data in numeric column in databse. If string data is numeric type then oracle server implicit convert it. Otherwise raise INVALID_NUMBER Exception.
- 7. Prepared By JAVATECH “Search us in The World” 7 See Example. ZERO_DIVIDE Exception ( in java is called ArithmeticException ) When you try to divide any number by zero it generates ZERO_DIVIDE exception. Watch example…..
- 8. Prepared By JAVATECH “Search us in The World” 8 Now I will discuss user defined exception Previous program system automatically know number is divide by zero in z:=x/y line. But user defined exception we check if y enter number is equal to zero then we explicitly generate exception by using raise keyword. And in raise keyword we specify exception identifier name. E.g MyExec Exception; here MyExec is a identifier which is declared Exception type. And we check y is zero or not if zero raise MyExec If y=0 then Raise MyExec; And in Exception block previously we specified ZERO_DIVIDE system defined Exception. But here we use our defined as “MyExec” see how… When ZERO_DIVIDE then Dbms_output.put_line(‘Divide by zero is not possible’); End But User defined we write When MyExec then Dbms_output.put_line(‘Divide by zero is not possible’); End;
- 9. Prepared By JAVATECH “Search us in The World” 9 See Exmple….. RAISE_APPLICATION_ERROR Is there any technique without define exception block we can specify our user defined error message with our own error no. Yes there is technique called RAISE_APPLICATION_ERROR(erro_no,err_message) Error_no range should be -20,000 to -20,999 [ give the - minus symbol ] Message upto 2048 byte long Where to specify it. You will write in begin section directly with errno and err message. Generally it is defined in your user defined exception. After use
- 10. Prepared By JAVATECH “Search us in The World” 10 raise_application_error your program is terminated there. No further executed. See Examples….. with zero divide exception FIND MORE SEARCH US IN FACEBOOK “JAVATECH 123” ***********Thanking You.************