Hi.
I don't know a lot about databases - I believe that there are choices
sometimes between Microsoft Access and "SQL". I currently have customer that
has 1800 records (address, case history, social services data...ect.). They
are interested in moving to Access.
This is a good reason to network with other specialists/consultants. When a
customer asks questions that are outside your area of expertise, know which
expert to ask or which expert to recommend to your customer.
1800 records is a small database, which Access can handle and other
client/server databases are probably overkill. However, there are many other
considerations besides the present size, such as:
1.) Is it mission-critical? Does the customer need the database up and
running during all business hours? Would revenues be lost if the database
was off-line for half an hour or more while the Access developer restored
from the backup? If so, a client/server database is the better choice. If
the customer can deal with restoring from a backup of the file from the night
before, then Access is acceptable.
2.) Does it require that all transactions (record entries) be correct and
recoverable? If Access fails, the last entries may not have been saved.
Client/server databases use transaction logs to either roll back or roll
forward transactions so that the data is consistent. Access doesn't have
this capability. For example, if an entry were made to delete $100 from a
savings account and add $100 to a checking account, but the power went out
before the second part of the transaction executed, the client/server could
recover to a point just before this transaction started so that the $100
would still be in the savings account. Access would have $100 missing from
the savings account and it never would be transferred to the checking
account. Clearly, the client/server would be the better choice in this case.
3.) How many concurrent users will use a desktop application? Access can
handle 20-30 concurrent users if the database is designed well and there
aren't heavy update, append, and delete operations. If the database has
heavy usage such as this, five or six users might be more reasonable for
sufficient performance. For read-only usage (especially Web-based apps),
Access can handle much more, possibly up to 100-200 concurrent users,
depending upon the design and complexity of the database, and the network
capabilities.
4.) Is security required? Anyone who has access to the Access database can
copy the necessary files and get the tools necessary to retrieve the data,
even if Access user-level security has been implemented. If it's
confidential data or data that needs security, then Access is not among the
choices.
5.) How big will it grow? Access 2000 and newer versions can handle 2 GB
database files. If the customer needs more room than this within the next
one to two years, then use a client/server database.
6.) How robust does it need to be? For a heavy-duty database that must be
reliable at all times, use the client/server.
Remember that in each of these cases, if a client/server database engine is
selected for data storage and data manipulation, Access can be used to
develop a front end (user interface) to the data, so the choices aren't
mutually exclusive.
HTH.
Gunny
See
http://www.QBuilt.com for all your database needs.
See
http://www.Access.QBuilt.com for Microsoft Access tips.
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