In COBOL, what is the role of the SORT statement when handling duplicate records?
- It arranges records in ascending order based on the specified key
- It has no impact on duplicate records
- It removes duplicate records from the file
- It separates duplicate records into a separate file
The SORT statement in COBOL, when used with the DUPLICATES phrase, segregates duplicate records into a separate output file, allowing for distinct processing of such records.
You are tasked with processing sales transaction data, and some transactions may be recorded twice due to system glitches. How would you ensure that such duplicate transactions are detected and managed correctly?
- Implement a check during data entry to prevent duplicate transactions
- Perform a sequential search on the transaction data to identify duplicates
- Use a COBOL program to perform a hash function on transaction IDs
- Utilize a COBOL file control system to flag and handle duplicate transactions
Utilizing a COBOL file control system to flag and handle duplicate transactions is a robust approach. This involves setting up mechanisms to detect and manage duplicates during the processing of sales transaction data, ensuring data accuracy and integrity.
In a COBOL program, you need to execute a stored procedure to update customer records in a database. How would you achieve this?
- EXEC SQL CALL
- EXEC SQL DECLARE
- EXEC SQL OPEN
- EXEC SQL UPDATE
To execute a stored procedure in COBOL, you would use the EXEC SQL CALL statement. This statement is specifically designed for invoking stored procedures in a database, allowing you to update customer records or perform other operations.
In a complex COBOL program, you notice the extensive use of the "LINKAGE SECTION." What is the primary purpose of this section, and when is it commonly used?
- It declares variables used only within the called subprogram
- It defines data items shared between a calling program and a called subprogram
- It indicates the sequence of program execution
- It specifies the input-output operations for external files
The "LINKAGE SECTION" in COBOL is used to define data items shared between a calling program and a called subprogram. It allows data to be passed between programs, facilitating communication and data sharing in a modular and organized manner.
When defining a data type in COBOL, the _____ clause is used to specify the number of characters or digits that a field can hold.
- LENGTH
- OCCURS
- PICTURE
- SIZE
The SIZE clause in COBOL is used to specify the number of characters or digits that a field can hold. It helps allocate the appropriate amount of storage for a data item.
How is an indexed file different from a sequential file in COBOL?
- Indexed files allow direct access to records using a key, while sequential files are accessed sequentially from the start to end
- Indexed files are smaller in size compared to sequential files
- Sequential files are read-only, while indexed files support both read and write operations
- Sequential files are suitable for large datasets, while indexed files are better for small datasets
The primary distinction is that indexed files in COBOL enable direct access to records using a key, offering efficient retrieval based on specific criteria. In contrast, sequential files are accessed sequentially from the beginning to end, making them suitable for large datasets.
In an indexed file system, you notice that certain records are accessed frequently, while others are rarely accessed. How can you optimize the performance of record retrieval for frequently accessed records?
- Clustering frequently accessed records together
- Implementing a multi-level index
- Increasing the size of the index file
- Using alternate indexes
Clustering involves physically arranging records in the file so that frequently accessed records are stored close together. This reduces the number of disk accesses required to retrieve these records, thereby improving performance for frequently accessed data.
_____ is a strategy for handling duplicate records by aggregating data based on a common key.
- Aggregate
- Group By
- Rollup
- Summarize
The Group By strategy in COBOL involves aggregating data based on a common key, allowing for the consolidation and summarization of records with similar key values.
In COBOL, the "ELSE" clause is executed when the condition in the "IF" statement is _____
- FALSE
- False or Undefined
- TRUE
- Undefined
The "ELSE" clause in COBOL is executed when the condition in the "IF" statement is False. If the condition is True, the statements following the "ELSE" clause are skipped. If the condition is False or Undefined, the "ELSE" clause is executed.
When might you use the REDEFINES clause in a COBOL program?
- To control program flow
- To declare a new variable
- To optimize program execution
- To represent the same data in different formats
The REDEFINES clause in COBOL is used when you want to represent the same data in different formats. It helps conserve memory by allowing different data items to use the same storage space.