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A.06.30 Release Notes
When using database locks and transactions an unlock is now delayed
until the database transaction is finished (either committed or rolled back).
This makes it easier to adopt database transactions with existing software and
avoids possible interactions between transactions and database locks by
applications which may result in a deadlock.
The following example demonstrates this:
! Begin transaction
DBBEGIN("",1,S(*))
...
! Write-Lock customer 12345
PREDICATE Q$ FROM "CUSTOMER","CUSTNO","=",12345
DBLOCK(Db$,Q$,6,S(*))
...
! Update customer record
DBUPDATE(Db$,"CUSTOMER",1,S(*),"@",Buf$)
...
! Unlock customer. The lock is not freed until the transaction completes.
DBUNLOCK(Db$,"",1,S(*))
...
! This will also release freed locks
DBCOMMIT(1,S(*))
...
With previous Eloquence versions database locks were independend
from transactions. This could lead to a situation where a record is
locked by a transaction (because it was modified in a transaction)
and another user aquires a lock and then tries to update the same
record.
The lock status is marked as "PENDING" in the http status
display and dbctl output.
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