FairCom RTG COBOL Edition User's Guide

Transaction Control - Why you should want it

Transaction control provides two extraordinarily powerful tools for your applications - atomicity of operations, and recovery of data. There are four key components of any complete transactional system, collectively referred to as ACID:

• Atomicity - Grouping of database update operations into all-or-nothing commits;
• Consistency - The database remains in a valid state due to any transaction;
• Isolation - Concurrent transactions do not interfere with each other outside of well-defined behaviors;
• Durability - Committed transactions are guaranteed to be recoverable, even if the data and index files are inconsistent.

FairCom RTG is fully ACID compliant and as such, FairCom RTG provides the highest levels of transaction integrity.

Some differences exist in the transaction handling support provided by ACUCOBOL, Micro Focus, isCOBOL, and RM/COBOL:

	ACUCOBOL	Micro Focus	isCOBOL	RM/COBOL
START TRANSACTION	Transaction is explicitly started using START TRANSACTION directive.*	Not supported Transaction is automatically started during first Update statement.
COMMIT TRANSACTION	Supported	Supported
ROLLBACK TRANSACTION	Supported** Allows rollback of updates only if a file has been defined as WITH ROLLBACK.	Supported

*

In ACUCOBOL a transaction is explicitly started using a START TRANSACTION directive.

**

An ACUCOBOL program allows rollback of updates only if a file has been defined as WITH ROLLBACK.

The FairCom RTG files are created PREIMG by default therefore they are transaction ready and support ROLLBACK out-of-the-box. There is no need to enable <transaction logging> to use ROLLBACK.