iX V6.5 (30391-90011)

318 Chapter7

Logging and Recovery

Logical Transactions

is returned indicating the failure of the intrinsic, the status condition must be checked

before proceeding further or rolling back the entire transaction.

As with nondynamic transactions, the placement of DBLOCK calls either before or after

DBXBEGIN is up to the programmer. A program with Multiple RIN (MR) capability can

apply multiple locks with a dynamic transaction. MR capability is described in appendix D.

Dynamic transactions are not allowed when a database is opened in mode 2, because mode

2 does not enforce locking or guarantee transaction independence.

An example of strong locking follows:

DBLOCK for account 2,18,34

Lock should precede DBXBEGIN call.

DBXBEGIN

DBGET data for account 2

DBPUT data for account 34

DBGET data for account 18

DBDELETE data for account 18

DBXEND

DBUNLOCK for all accounts

DBUNLOCK must follow DBXEND

call.