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System tables are used by Access to make databases function correctly. With a few exceptions, there is very little information available online about most of the system tables.
The purpose of this article is to summarise known information about Access system tables.
It is also an invitation to other developers to add to this pool of knowledge
Some system tables can be viewed & a few can be edited
However you should only do so ....IF YOU ARE ABSOLUTELY SURE WHAT YOU ARE DOING
Incorrectly editing system tables may corrupt your database or prevent you opening it
This article describes various tests done to compare different approaches to coding:
1. Handling nulls: Trim / Len / Nz
2. CurrentDB vs DBEngine(0)(0)
3. DoEvents vs DBIdle.RefreshCache
4. HAVING vs WHERE
5. Conditional Updates: If..ElseIf..End If / Select Case / Nested IIf / Switch / Lookup Table
6. Query vs SQL vs QueryDef
Example databases are provided so the tests can be done on your own workstations
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This page contains links to some longer articles discussing specific issues in Access in greater detail.
It is intended that the number of articles will be significantly increased in the coming months so please check back again regularly.
SECTION currently not in use
There are many things that developers can do to improve the security of their applications (both design & data). However, no Access database can EVER be made 100% secure. A capable and determined hacker can break any Access database given sufficient time and determination.
The older MDB / MDE file format is FAR LESS SECURE than the newer ACCDB / ACCDE format. Whilst this is hardly news to many developers, I’ve had a few requests to provide more details to justify this statement.
During development work, all of us will want to ensure that tasks are completed as quickly as possible. However, it is not always obvious that the current design is inefficient until performance slows to a crawl and clients start to complain.
Where queries or VBA SQL statements are concerned, help is available by making use of the ShowPlan feature which is available with both the JET database engine (up to A2003) and the newer ACE engine (A2007 onwards). The ShowPlan option prints the query's plan to a text file so you can review and, if possible, improve the design.
The purpose of this article is to provide more details about the ShowPlan feature for which little documentation is available online
This article summarises many of the actions that all Access developers should do when deploying databases in a multi-user environment.
These will significantly reduce the risk of data corruption as well as minimising the possibility of data being misused or stolen
Multivalued fields (MVFs) were a new feature introduced with Access 2007
This article explains what MVFs are and how they can be used.
Although often attractive to new users, most experienced developers avoid them completely.
This article explains why this feature is really not a good idea