Finding and Deleting Unused Access Objects and Code

How Unused Objects and Code Get Created

It's very easy to create objects in a Microsoft Access database whether it's an MDB, ADP, or ACCDB. During development or interactively analyzing data, queries and code are commonly created and tested. Some are kept for future use, but others remain even if they're no longer necessary. It's usually because you don't want to immediately delete these objects in case you need them in the future. Later, one forgets why the objects exist.

Over time, the accumulation of unnecessary and unused objects can become significant and distracting. It creates confusion when trying to figure out how all the database objects work together, and you may end up fixing and maintaining objects that aren't even used.

Fear of Deleting Unused Objects

These are common experiences among MS Access users and developers. Fortunately, there's a better way than just hoping you didn't make a mistake.

Finding Unused Objects

The process of finding unused objects is non-trivial since we're trying to discover what doesn't exist. In order to determine which objects are not used, we need to first determine where every object is used (an object or code cross-reference). Only after that's known, can one determine which objects are unused.

Where Objects and Code are Used

Microsoft Access objects and code can be used in a variety of places which makes it very challenging to determine with 100% accuracy that all the references are detected.

Where Tables and Queries are Referenced

For example, here are some places where Access tables and queries can be referenced:

• Tables reference each other through referential integrity
• Queries
• From the Record Source property of forms and reports
• On the Row Source property of field lookup definitions
• The Row Source property of combo box and list box controls on forms and reports
• Command bar or Ribbon
• Macro commands such as OpenTable
• Module code from:
  • DoCmd references for opening a table, import/export, etc.
  • Through DAO and ADO recordset references
  • TableDefs collections, etc.

  The references could be an explicit table name as a string or constant, or a variable or expression that's determined at runtime.

• From table driven systems where a table may be invoked via a value in a table
• Interactively, where you don't know what the user is doing with the table but you certainly can't delete it.

Form and Report References

Similarly, forms and reports can be referenced in a variety of places:

• The Startup form property of the database
• The SourceObject of a subform or subreport
• The parameter of a query that references a control on the form/report. This can be a standalone query or the SQL string of a form/report Record Source property or one of its control's Row Source property
• A form or report control that references a control on another form/report
• A parameter passed to a VBA or user defined function
• Command bar or Ribbon references
• Macro commands opening a form/report, referencing a control in an expression or condition, etc.
• Module commands that can open or reference forms or reports in a variety of ways
• Table driven systems where form and report names are stored in a table
• Interactive use of forms and reports outside programmatic control

Module and Procedure References

Unused classes, procedures and variables are very common. Code can be used not only within modules but also through other objects:

• Macros can call functions via the RunCode command
• Queries can reference user defined functions as criteria or output columns
• A form or report event can call functions
• A form or report control can call functions in its ControlSource property

These non-module code references are very powerful but can also cause maintenance problems because they are outside the scope of the VBA compiler. That is, the VBA IDE's compile command can consider the project to be compiled, but can't detect invalid references to the code from these non-module places (misspelled function names, invalid or incorrect number of parameters, etc.).

Comprehensive Object and Code Cross-Reference with Total Access Analyzer

Fortunately, our Total Access Analyzer program performs detailed analysis among all the Access objects to generate the most comprehensive usage across your database. It can't determine certain things like non-explicit object references in code, references based on table driven systems, or interactive use of the objects, but it does capture most of the other references and all explicit references. By determining all the places where objects are used, it then reports the objects that are not used.

Unused Object Analysis

After you document your database by selecting all your objects (the object cross-reference wouldn't be comprehensive if you didn't document everything) and check the module cross-reference option, the results include object and module cross-reference (XREF) and unused object and code information.

In addition to unused code, Total Access Analyzer also detects:

• Unreferenced variables, which are variables assigned a value but never used (why bother?)
• Procedures that should be private rather than public since they are only used in their module
• Empty procedures (common when an Event Procedure is created but never filled)

Viewing the Unused Objects and Code

The results can be viewed through the Documentation Explorer under Suggestions:

When your cursor is on a particular issue, the Design button is enabled to let you open that object in design mode so you can review and apply the changes you want to make. This is particularly useful for the unused VBA code issues since you can jump directly to that procedure in the module editor.

The filter feature lets you specify the suggestion types you want to see:

Unused Object and Code Reports

Total Access Analyzer offers several reports for unused objects:

• Unused Tables
• Unused Queries
• Unused Forms
• Unused Reports
• Unused Macros (including sub macros)

For VBA module code, these unused reports are available:

• Unused Procedures (Subs and Functions)
• Unused Properties (Let, Get, and Set Statements)
• Unused Constants and Variables (local, module and global levels)
• Unused User Defined Types

Total Access Analyzer lets you select these reports under the Suggestions category:

Eliminating Unused Objects and Code

Just because Total Access Analyzer says an object is not used does not mean you should automatically delete it.

First of all, a table, query, form, report, or macro can be used interactively from the Navigation Pane or database container and would not be detected by Total Access Analyzer. So this requires knowledge of how the database is used by the users and developers before deleting them.

Secondly, while it's pretty easy to confirm a variable isn't being used in code, it's not so clear with other objects. You need to confirm that objects aren't being used in ways that Total Access Analyzer can't detect. An example would be references based on values in a table or expressions in code, or usage by another application.

Assuming you've determined which items are not used, you are ready to delete them. Be sure to make a backup, then test your new database after your changes.

It's also a good idea to rerun Total Access Analyzer, because after you delete your objects, there may be new unused objects which were only referenced by your deleted objects.

Conclusion

Determining where Access objects are used and getting rid of unused objects was one of the main reasons we originally created Total Access Analyzer. It's a fundamental part of professional application development, and we're pleased so many Access users and developers use our product. We hope you'll give it a try as well.

Some think that getting rid of unused objects and code is an unneeded luxury since these objects don't harm anything. That's true, but creating professional solutions involves doing things right, keeping things clean, and adopting Best Practices.

Eliminating unused objects and code in your database can significantly reduce the bloat and maintenance hassles of your Microsoft Access applications. It makes the database easier to understand, reduces the need to fix useless objects and code, and improves performance.

Getting rid of unused Access objects is one of the first things we do when taking over an existing database. We also use it during development to make sure we don't introduce unnecessary junk. During development, it's very easy to create and abandon queries, procedures, variables etc., so the less of those we keep, the better.

Good Luck!

Additional Best Practices for Microsoft Access Database Development