In COBOL, what is the primary purpose of the "NOT ON EXCEPTION" clause?
- To ensure that exceptions are handled only once
- To exclude specific exceptions from being handled
- To force the program to terminate on any exception
- To handle exceptions that do not match the specified conditions
The "NOT ON EXCEPTION" clause in COBOL is used to exclude specific exceptions from being handled by the associated exception-handling routine. It allows for fine-grained control over exception handling, ensuring that only relevant exceptions are processed while others are ignored.
What are the common methods for handling database errors in a COBOL program?
- Ignoring errors for better performance
- Manual logging of errors in a separate file
- Use of SQLCODE and SQLSTATE
- Using only COBOL DISPLAY statements
In COBOL, handling database errors involves checking SQLCODE and SQLSTATE after each SQL operation. These codes provide information about the success or failure of the database operation and help in implementing appropriate error-handling logic.
Explain the concept of "nested scope" in COBOL with an example.
- It allows variables to be shared across all program blocks
- It limits the visibility of variables to the outermost program block
- It restricts the use of variables to the main program only
- Nested scope refers to the ability to define variables within inner program blocks that are only visible within those blocks
In COBOL, nested scope allows the definition of variables within inner program blocks, making them visible only within those blocks. For example, declaring variables inside a paragraph or a SECTION creates a nested scope.
COBOL, what is "ON EXCEPTION UNDO" used for in error handling?
- To display an error message to the user
- To ignore exceptions and proceed with the program execution
- To roll back changes made to the file in case of an exception
- To terminate the program when an exception occurs
"ON EXCEPTION UNDO" in COBOL is used to roll back changes made to the file in case of an exception. It ensures data consistency by undoing any modifications made before the exception occurred.
In a COBOL program, when using a PERFORM loop with the VARYING clause, what is the role of the INDEX variable?
- It is not applicable to PERFORM loops with the VARYING clause
- It is used to control the loop execution by specifying the increment value
- It represents the total number of iterations in the loop
- It serves as a loop counter, indicating the current iteration
The INDEX variable in a PERFORM loop with the VARYING clause is crucial as it acts as a loop counter, keeping track of the current iteration. Program logic can be based on the value of the INDEX variable within the loop.
What does VSAM stand for in the context of COBOL file handling?
- Variable Storage Allocation Method
- Very Sequential Access Method
- Virtual Storage Access Method
- Volatile Storage Access Module
VSAM stands for Virtual Storage Access Method in the context of COBOL file handling. It is a file storage access method used to organize records in a file in a way that allows direct access to data based on the key.
Your COBOL program needs to maintain a counter that keeps track of the number of times a specific operation is performed. Which type of variable is suitable for this task?
- PIC 9(3) USAGE DISPLAY
- PIC 9(4)
- PIC 9(5) USAGE COMP-3
- PIC S9(6) USAGE COMP
For maintaining a counter in COBOL, PIC S9(6) USAGE COMP is appropriate. It is a signed numeric type that efficiently stores and increments numeric values.
How are COBOL group data items different from elementary data items?
- Group data items are always numeric, whereas elementary data items can be alphanumeric
- Group data items can contain other data items, including other groups, while elementary data items cannot
- Group data items cannot have a picture clause, unlike elementary data items
- Group data items do not support the REDEFINES clause, unlike elementary data items
COBOL group data items differ from elementary data items in that they can contain other data items, including other groups. This hierarchical structure allows for better organization and abstraction in the data design of a COBOL program.
Can you use the REDEFINES clause to redefine a group data item in COBOL?
- No, REDEFINES can only be applied to elementary items
- No, group data items cannot be redefined in COBOL
- Yes, but only if the group data item has a subordinate item
- Yes, it allows a group data item to be redefined by another group or elementary item
In COBOL, the REDEFINES clause can be used to redefine a group data item. It allows a group data item to share the same storage space with another group or elementary item, providing flexibility in data structure representation.
The "AT END" clause is often used in conjunction with the "NOT ON EXCEPTION" clause to handle errors that occur at the _____ of file processing.
- Beginning
- End
- Middle
- Start
The "AT END" clause in COBOL is used in conjunction with the "NOT ON EXCEPTION" clause to handle errors that occur at the end of file processing. This is useful for performing cleanup or finalization tasks before the program concludes.