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CICS READNEXT - Read Next

CICS READNEXT provides read next management capabilities, enabling read next processing and output processing in CICS environments. It provides efficient read next capabilities for CICS applications.

What is CICS READNEXT?

CICS READNEXT provides read next management capabilities, enabling read next processing and output processing. It provides efficient read next capabilities, allowing applications to manage read next operations.

Command Syntax

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EXEC CICS READNEXT
    [RESP(response-code)]
    [RESP2(response-code-2)]
END-EXEC.

Parameters Explained

RESP Parameters

Response codes returned by the command:

  • RESP: Primary response code - indicates the success or failure of the read next operation
  • RESP2: Secondary response code - provides additional error information when RESP indicates failure
  • Always check these codes for command success before proceeding with data processing
  • Handle command failures appropriately to prevent application errors

Read Next Types

1. Basic Read Nexts

  • Basic read nexts: Standard read next operations that handle simple read next processing without special formatting
  • Mapped read nexts: Read next operations that use predefined field mappings to structure read next data
  • Unmapped read nexts: Raw read next operations that handle unstructured read next processing without predefined field mappings
  • Custom read nexts: Specialized read next operations designed for specific application requirements

2. Advanced Read Nexts

  • Advanced read nexts: Complex read next operations that handle sophisticated read next processing and validation
  • Secure read nexts: Read next operations that include encryption and security features for sensitive read next processing
  • Encrypted read nexts: Read next operations that automatically encrypt read next data
  • Compressed read nexts: Read next operations that handle compressed read next streams and automatically compress read next data

3. Specialized Read Nexts

  • Specialized read nexts: Read next operations tailored for specific protocols or communication methods
  • High-performance read nexts: Optimized read next operations designed for maximum throughput and efficiency
  • Low-latency read nexts: Read next operations optimized for minimal delay and real-time processing requirements
  • High-throughput read nexts: Read next operations designed to handle large volumes of read next processing efficiently

Implementation Example

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WORKING-STORAGE SECTION.
01 WS-RESPONSE            PIC S9(8) COMP.
01 WS-RESPONSE2           PIC S9(8) COMP.
 
PROCEDURE DIVISION.
    * Read next operation
    EXEC CICS READNEXT
        RESP(WS-RESPONSE)
        RESP2(WS-RESPONSE2)
    END-EXEC.
    
    IF WS-RESPONSE NOT EQUAL DFHRESP(NORMAL)
        EXEC CICS WRITE OPERATOR
            TEXT('READNEXT command failed')
        END-EXEC
        EXEC CICS RETURN END-EXEC
    END-IF.
    
    * Read next operation completed successfully
    * Continue processing

Read Next Processing

1. Read Next Preparation

Read next preparation includes:

  • Read next validation - ensuring the read next operation is properly configured and authorized
  • Read next formatting - preparing data structures and buffers for read next data
  • Read next encoding - setting up proper character encoding and data transformation
  • Read next processing - initializing the read next operation and preparing for read next processing

2. Read Next Transmission

Read next transmission includes:

  • Read next routing - directing read next data to the appropriate processing location
  • Read next delivery - ensuring read next data reaches the correct destination within the application
  • Transmission confirmation - verifying that read next was completed successfully
  • Error handling - managing transmission failures and implementing retry mechanisms

3. Output Management

Output management includes:

  • User management - handling user sessions and maintaining connection state
  • Output formatting - structuring read next data for presentation or further processing
  • User experience - ensuring smooth data flow and responsive application behavior
  • Performance optimization - maximizing read next efficiency and minimizing resource usage

Common Response Codes

Success Response Codes

  • NORMAL (0): Read next operation completed successfully - read next processing was completed without errors
  • READNEXT (4): Read next operation completed - operation completed with read next-specific status

Error Response Codes

  • INVREQ (16): Invalid request - the read next operation parameters are incorrect or unauthorized
  • NOTFND (20): Resource not found - the specified read next resource does not exist
  • LENGERR (22): Length error - the read next data length exceeds expected limits
  • READNEXT (24): Read next error - a read next-specific error occurred during the operation

Best Practices

1. Read Next Preparation

  • Prepare read next appropriately - ensure all necessary resources and configurations are in place
  • Validate read next content - verify that read next data meets expected format and quality standards
  • Handle different read next types - implement flexible processing to accommodate various read next processing formats
  • Ensure read next integrity - maintain data consistency and prevent corruption during read next processing

2. Error Handling

  • Check all response codes - always examine both RESP and RESP2 for complete error information
  • Handle read next failures - implement appropriate recovery mechanisms for failed read next operations
  • Implement retry logic - provide automatic retry capabilities for transient failures
  • Log error conditions - maintain detailed logs for troubleshooting and monitoring purposes

3. Performance Optimization

  • Minimize read next operations - reduce unnecessary read next calls to improve overall performance
  • Use efficient read next formats - choose appropriate data formats to minimize processing overhead
  • Optimize user updates - streamline user interface updates to reduce response time
  • Manage user resources - efficiently allocate and manage system resources for read next operations

Explain It Like I'm 5 Years Old

Imagine you're reading a book page by page:

When you want to read a book, you start at the first page and then read the next page. If you read the next page, you learn what it says. If you don't read the next page, you don't learn what it says.

CICS READNEXT is like reading the next page of a book. The computer program reads the current page and then reads the next page. If it reads the next page, it learns what it says. If it doesn't read the next page, it doesn't learn what it says.

Just like you read the next page of a book, the computer program reads the next page of a file!

Exercises

Exercise 1: Read Next Operation

Write a CICS READNEXT command to perform a read next operation.

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EXEC CICS READNEXT
    RESP(WS-RESPONSE)
    RESP2(WS-RESPONSE2)
END-EXEC.

Exercise 2: Read Next Processing

How would you implement comprehensive read next processing that handles different read next types and requirements?

Answer: Identify different read next types and appropriate handling, implement read next validation and encoding, handle different read next types and capabilities, implement proper error handling for read next failures, optimize read next operations for performance, and maintain read next integrity throughout the process.

Quiz

Question 1

What is the primary purpose of CICS READNEXT?

Answer: B) To provide read next management capabilities

Question 2

Which parameter specifies the response code?

Answer: A) RESP

Related Concepts

CICS Read Next Processing

Read next processing and output in CICS

CICS User Management

User management and user interaction in CICS

CICS Output Processing

Output processing and read next display in CICS