Chapter 21: Building Multiuser Applications ..............................................................................
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File location
File location can change the performance of your application more than you may think. Where
you locate your files depends on the environment. For example, if your network contains diskless
workstations, then you have no choice but to run the entire application from the server — an
unfortunate but unavoidable choice. However, if each workstation has a hard disk with plenty of
free space available, you might want to locate some files on the server and some on each worksta-
tion (although you probably should put all the files on each workstation except the data files that
will be shared by all users).Note
Splitting your database involves creating a back-end Access data file (.accdb or .mdb, containing data tables
only) and a front-end database (an Access data file containing macros, code modules and form, report, and
query objects). The split-database method of maintaining your applications has advantages in almost any envi-
ronment, but it offers you even more advantages in a networked multiuser environment. (I cover the advan-
tages of splitting Access databases in much greater detail in the “Splitting a Database for Network Access”
section, later in this chapter.)
In the following sections, I cover some of the advantages and disadvantages of different file-
location scenarios.All files on the server
The primary advantage of locating all your application files on a server is that updating your appli-
cation is easy because everything is in a single location. You can easily post a new .accdb or
.mdb file on a file server or in a shared folder in a Windows network.Caution
The disadvantages, however, far outweigh the advantage. Performance is poor because every read, write, or
execute request must first cross the network to the server, and then a response must be sent back around the
network to the client. This approach greatly increases network traffic, especially in an environment with many
users. Try to avoid this scenario, if possible.
Distributed installation
A distributed installation is a good choice for most environments. In this design, you install a copy
of Access and the front-end database on the user’s local machine, leaving the back-end database
application and linked data files on the server. Less network traffic is generated and less time is
spent waiting for requests to be sent back and forth around the network. This installation allows
for moderately simple upgrades because the majority of the most volatile files are in one central
location.One problem you may experience with this approach is decreased performance when several users
access your application databases at the same time.