TRANSTART Statement

Marks the start of a transaction, preceding any READ/WRITE operations on the database included in the transaction.

Syntax

TRANSTART {transaction-information} {SETTING setting-var} [THEN statement(s) | ELSE statement(s)]

Syntax Elements

transaction-information
Optional text, specified as text within double quotes or a variable, to be saved in the transaction-start record. It can be used to identify a particular transaction or iteration of a repetitive transaction. You can only use transaction-information if Transaction Logging is installed and enabled, when it can be used when listing a clean log or during a TL-RESTORE. It is not used in Transaction Handling.

setting-var A variable that is set to a value corresponding to an error code if the ELSE clause is taken, which occurs when transactions have been disabled or the process is already inside a transaction.

statement(s) Either a THEN or an ELSE clause (or both). A statement must be included. The THEN clause is executed if the Transaction Start is successful. The ELSE clause is executed if the transaction start fails.

Operation

If no transaction-information parameter is supplied then the file-name and item-id containing the program performing the transaction along with the time and date is substituted. More than one transaction can occur within a single DataBasic program. A single transaction can span several CHAINed programs. Transactions cannot be nested. A TRANSTART statement followed by another TRANSTART statement without an intervening TRANSEND or TRANSABORT statement causes a run-time error. The ELSE clause in the second TRANSTART statement is then executed. Error codes returned to setting-var can be:

Item Locks

Item locks released within a transaction are held until the transaction is committed or aborted.

Comments

Text is only written to the clean log if there is something in the transaction. So if you use TRANSTART, then TRANSEND with nothing in-between, the TRANSTART/TRANSEND is not written to the log.