[AccessD] Defense of Access

Hi Marty,

The version of Jet used by Access since A2K has optional record-level
locking.  This was a significant improvement for me.

Thanks for this discussion - I had never heard before of two versions of
Jet.  But it does sound as though the two versions are very different and
may not deserve to be argued as if they were similar.

IMO, the primary problem with Access is simply that untrained inexperienced
people try to take Access beyond what they're capable of (and they don't
even know they're not!)  A person at one of my customers uses only macros,
and he tells other people that I don't know what I'm doing even though the
system they have includes over 60K lines of code.  Luckily his boss (my
invoice approver) knows the difference!

Dan
 

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of MartyConnelly
Sent: Saturday, April 01, 2006 3:16 PM
To: Access Developers discussion and problem solving
Subject: [AccessD] Defense of Access

Someone asked me for a counter argument regarding the use of Jet and by 
default Access.
So here is something I pieced together from some blogs, I can't remember 
seeing anything posted here
on Jet version's Red and Blue.
 
Most of these database types have good arguments against using JET but
don't realize that Active Directory Services and Exchange are built on 
top of JET.
Don't tell me, they would throw out these applications because of their
prejudices. Yes, Mr CIO, I know, but we have to get rid of all those
Active Directory Services that you just spent two years installing because
Gasp! it's based on a JET database engine.  I really like bringing this up
to the one trick pony Oracle types who work on Windows. It is fun to watch
them squirm for awhile; although a knowledgeable db type can counter this.

 So here is some info to throw at them.

JET was originally part of Access (or FoxPro for some of the very early MS
versions). It split into Jet Red and Jet Blue. Jet Blue was used for
MSExchange and Active Directory and is shipped with Windows 2000 and
later. It's now known as ESE. Jet Red was still shipped with Access. All
throughout it's history, Jet Red has been freely distributable. Many many
many VB apps were shipped with Jet Red.

JET Red was an ISAM originally developed by Microsoft for BC7, compiled
basic. JET Blue was originally developed by Microsoft as a prospective
upgrade for Access, but it was never used in this role. JET Red and JET
Blue began sharing the common JET moniker in the Spring of 1990 when a
query technology, QJET, was developed that would host on both Red and
Blue.

JET Blue went on to be used by Microsoft Exchange, Active Directory and
many many other Windows services. JET Blue was a private API for many
years, but became a published API in April of 2005 when three middle ware
applications not covered by the Windows EULA chose it as their data store.
Now anyone can use JET Blue.

Extensible Storage Engine (ESE) -- the Active Directory database engine.
ESE (Esent.dll) is an improved version of the Jet database that is used in
Microsoft Exchange Server versions 4.x and 5.5. It implements a transacted
database system, which means that it uses log files to ensure that
committed transactions are safe.
The ESE engine used by Active Directory is based on Microsoft's Jet
database technology. Jet uses a b-tree file structure with transaction
logs to ensure recoverability in the event of a system or drive failure.

JET Red is a file sharing technology with page level locking and best
effort crash recovery. JET Blue on the other hand is designed to be
embedded in a server application, does not share files, has write ahead
logging for guaranteed crash recovery and has record level locking. JET
Blue does not ship with a query engine but instead relies on applications
to write their own queries as C++ ISAM code.

With the release of Access 12 the Jet Red development team has been split
off from it's old SQL Server department and is free to develop on it's own.


Extensible Storage Engine API's
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ese/ese/ext
ensible_storage_engine_errors.asp

Access 12's new data engine ACEDB
http://blogs.msdn.com/access/archive/2005/10/13/480870.aspx


-- 
Marty Connelly
Victoria, B.C.
Canada



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