Database Locks - or who is in my database???
The fifth in an occasional series of rants by Chris
Early Morning 7:00am, I shouldnít have drunk that much on a school night! Slightly
(very) hung over I stager in to the office to be confronted by angry operations
"This Bloody system
youíve written has fallen overÖagain".
"Iíve told you before " I reply "Just restore the backup and run
it again the missing files should have turned up by now".
"We canít" they reply as one "There
is somebody in the database and we donít know who it is".
If you develop multi user access databases then you will know how terrifying the phrase
"There is somebody in the database and we donít know who it is" can be. Because there is no way to find out who
is in a database using the tools provided with Access. The only alternative is to phone up all the known users one
by one and visit each of those who donít answer to make sure they havenít left the system running on their machine. Yet
again I find myself wishing that the Access development team would pay a visit
to a taxidermist.
Luckily that guru of all things John Hawkins has
now waded through MS Technotes & produced a must-have application for Access
It is the Database Launcher which as well as launching databases
tells you who is in them. I can
also vouch that from personal experiences that it cures hangovers! With this neat little gizmo another
headache you could do without is eliminated. Hurrah!
For those of you
who want to know more about locking in Access there is a full description here.For those of you who just want to know
the basics they are these.
open an Access MDB for updating (ie not read-only) an LDB file is created to
handle locking of records. The LDB
file is created in the same directory so users must have access to
create/delete/modify files in the directory.
The maximum number of users who can access the same db is 255.
However if you are running systems of any serious size with
lots of users I suggest you move the database engine to SQL server, itís a lot more reliable than using an
If you have any comments about this article or
would like to suggest other niggles with Access please drop me a line at Contact
Chris Shepherd is an MCSD working for an Investment
Bank in the UK and now never drinks heavily during the week. Weekends however are a different matter.