When implementing file locking, the _______ and _______ modes are used to specify the type of access allowed to files.
- Open, Close
- Read, Write
- Sequential, Indexed
- Shared, Exclusive
In COBOL, file locking mechanisms utilize two modes: Shared and Exclusive. Shared mode allows multiple users to read the file simultaneously, while Exclusive mode grants exclusive access to a single user for both reading and writing operations. These modes help control access and prevent conflicts among concurrent users.
In a large-scale COBOL application, you have to manage multiple alternate indexes for an indexed file. What considerations should be taken into account to optimize performance and minimize conflicts?
- Option 1: Use a single alternate index for simplicity
- Option 2: Opt for as many alternate indexes as needed without restrictions
- Option 3: Limit the number of alternate indexes and carefully choose key fields
- Option 4: Choose any fields for alternate indexes to enhance flexibility
Limiting the number of alternate indexes and choosing key fields judiciously is crucial. Each alternate index adds overhead, so selecting only necessary indexes and optimizing key fields ensures better performance and reduces potential conflicts in large-scale applications.
What considerations should be taken into account when using the CONTINUE statement for error handling?
- It can be used to retry the operation that caused the error
- It is reserved for informational messages
- It is used to terminate the program
- It should be avoided for error handling
The CONTINUE statement can be used for error handling by allowing the program to retry the operation that caused the error. Care should be taken to avoid infinite loops and ensure that the error is appropriately handled.
When an error is handled using the "CONTINUE" statement, the program _____ executing the next statement after the error.
- Halts
- Restarts
- Resumes
- Skips
When an error is handled using the "CONTINUE" statement in COBOL, the program resumes executing the next statement after the error. The "CONTINUE" statement allows the program to proceed without being terminated by the error.
What is a COBOL group data item?
- A data item defined at the group level in COBOL
- A data item that groups multiple values together
- A data item that only contains elementary items
- A data item with a picture clause
A COBOL group data item is defined at the group level and serves as a container for other data items. It can include both elementary and other group data items, providing a way to structure and organize related data in a program.
In COBOL, what is the LEVEL number used for in the data description entry (FD)?
- To assign a priority level to the data item
- To define the number of occurrences in an OCCURS clause
- To indicate the level of nesting in nested programs
- To specify the hierarchy of a record
The LEVEL number in COBOL's FD (File Description) entry is used to specify the hierarchy or level of a record. It indicates the position of a data item in the hierarchy of the record structure.
When working with indexed files, what is the purpose of the "alternate key" in performance optimization?
- To act as a backup key in case of primary key failure
- To add redundancy to the index file
- To improve search and retrieval performance
- To provide an alternative method for sorting the file
The "alternate key" in indexed files serves to enhance search and retrieval performance by providing an alternative means of accessing data. It allows for efficient retrieval based on criteria other than the primary key, optimizing file access.
What is the purpose of the "Input" file access mode in COBOL?
- To perform both read and write operations on the file
- To read records sequentially from the file
- To update records in the file
- To write records to the file
The "Input" file access mode in COBOL is used to read records sequentially from the file. It allows the program to retrieve data from the file but does not permit any changes or additions to the file.
What is the significance of using the CURRENT-DATE special register in COBOL?
- It is a placeholder for future date and time calculations
- It is used to declare variables for date and time storage
- It retrieves the system date and time during program execution
- It stores the current date and time when the program is compiled
The CURRENT-DATE special register in COBOL is used to retrieve the current system date and time during program execution. It provides a standardized way to access real-time information for various date-related operations.
What is the purpose of exception handling in COBOL file processing?
- To ignore errors and continue file processing
- To manage and respond to unexpected situations or errors that may occur during file operations
- To speed up file processing operations
- To terminate the program in case of any file-related issues
Exception handling in COBOL file processing allows programs to gracefully respond to unexpected situations or errors, ensuring a more robust and reliable file processing mechanism. It involves capturing and responding to errors to prevent program termination.