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Article #19557: New Interbase SQL Links support in BDE 5.01 (SQLINT32.DLL v5.01.24)

 Question and Answer Database

     FAQ: FAQ4557B - New Interbase SQL Links support in BDE 5.01 (SQLINT32.DLL v5.01.24)
Category: Database (InterBase)
Platform: All-32Bit
 Product: All-CBuilder,   BC++5.x,   C++Builder1.0,   C++Builder3.x,   C++Builder4.x,   Delphi2.x,   Delphi3.x,   Delphi4.x,   VdBase7.x,   

Question:

Does the Interbase SQL Links driver support Roles and 
additional transaction behavior?


Answer:

Please see the BDEREADME.TXT for additional information regarding
BDE and SQL Links v5.01.

Please note that the new BDE ALIAS configuration parameters
(COMMIT RETAIN, ROLE NAME, WAIT ON LOCKS) will show up only 
in newly created ALIASES.


InterBase Changes
-----------------
Transaction Isolation Levels & InterBase
----------------------------------------
By adding 4096 to the setting of DRIVER FLAGS in the
Borland Database Engine (BDE) configuration, you can
specify that the InterBase SQL Links driver should use soft
commits. Soft commits are a feature of InterBase that let
the driver retain the cursor when committing changes. Soft
commits improve performance on updates to large sets of
data. When not used, the BDE must re-fetch all the records,
even for a single record change. With soft commit the
cursor is retained, and a re-fetch is not needed. Soft
commits are never used in explicit transactions started by
BDE client applications. The soft commit property
corresponds to the COMMIT RETAINING transaction option in
the InterBase documentation.

  DRIVER FLAGS  Isolation level  Commit type
  ------------  ---------------  ------------
  0             Read committed   hard commit
  512           Repeatable read  hard commit
  4096          Read committed   soft commit
  4608          Repeatable read  soft commit

The 4096 driver flag bit only affects implicit transaction
behavior. Use the COMMIT RETAINING property to control the
default commit behavior of explicit transactions.

Roles
-----
InterBase allows users to log in by specifying a role.
ROLE NAME is a new BDE configuration parameter that allows
BDE clients to pass a role name. ROLE NAME can also be
passed as an optional parameter when using a TDatabase
component (Delphi and C++Builder). 

This information supersedes that in the InterBase 5.5
Operations Guide, which indicates that the BDE has no
property for specifying a role name.

Transaction WAIT
----------------
Currently, the InterBase SQL Links driver uses NOWAIT when
resolving lock conflicts and returns an error immediately
if there is a resource conflict. Setting the WAIT ON LOCK
configuration parameter allows SQL Links to use WAIT on
InterBase transactions. This can also be done by setting
the r/w database property dbWAITONLOCK to TRUE.

Explicit transactions
---------------------
The new BDE configuration parameter COMMIT RETAIN allows
explicit transactions to use soft commit. The new database
property dbCOMMITRETAIN also does this. Only explicit
transactions are affected. The existing driver flags are
still valid for explicit transactions.

  COMMIT RETAINING = TRUE    calls isc_commit_retaining()
  COMMIT RETAINING = FALSE   calls isc_commit_transaction()




7/13/99 10:21:26 AM
 

Last Modified: 01-SEP-99