The Microsoft Office suite of software was developed for novice users to suit those not necessarily interested in development. To simplify database development, Microsoft Access embeds database applications, developed using Microsoft VBA programming, with database tables, objects and other components. Microsoft Access stores these database components in a single file, using the .mdb extension.
Unlike most other database systems, Microsoft Access is configured with this single file format, which ensures that user access to tables, and their data, is dependent upon the stability of all other components embedded in the .mdb file. If there are problems or corruption due to any of the embedded components, the database and its data, becomes inaccessible. Also different versions of Microsoft Access use different methods of formatting components of the .mdb file such that it is not backwards compatible. In other words, Microsoft Access 2000 can be configured to interpret a database file created with Microsoft Access 97, but Microsoft Access 97 cannot interpret a database file created using Microsoft Access 2000. To eliminate the problems associated with this single file format, Microsoft Access provides a method to split your database files to separate the data tables from all other components. Splitting your Microsoft Access database files makes the data tables available should one of the other database components, stored in the file, present a problem.
To further extend the integrity of your databases, newer versions of Microsoft Access allow you convert the file format of your database files. If you have a database that is in the Microsoft Access 2002/2003, or older, format, you should convert your database files from the .mdb format to the .mde format. The .mde format allows you to limit database users from modifying database applications that you have established. The .mde format allows you to store the same information that is contained in .mdb files, except that the underlying VBA are pre-compiled and stored in machine code. This prevents database users from reading, changing or copying the source code of your applications. It also prevents users from creating, modifying or importing forms and reports.
The .mde formatted file act as an executable program. As such, you may not make edits directly to an .mde file. Any modifications to your applications must be made to the .mdb file and re-compiled to .mde format. It is recommended that you, first, split your database and, then, convert the front-end database file to .mde format. By splitting your database and converting the front-end to .mde format, you need only modify the front-end objects and functions. The back-end data tables remain consistent and require no modification. If you do not split the database, before converting to .mde format, you must take special precautions, to preserve the data tables, when modifying your database.
Creating an .mde database allows to you distribute your applications to clients with either retail or runtime versions of Microsoft Access installed on their computers. This provides a convenient method of distributing your applications while also protecting them from modification or theft. This method also has some limitations as follows:
| MDE Created With: | Retail or Runtime Version Needed |
|---|---|
| Microsoft Access 97 | Microsoft Access 97 |
| Microsoft Access 2000 | Microsoft Access 2000, 2002, 2003 |
| Microsoft Access 2002 | Microsoft Access 2002, 2003 |
| Microsoft Access 2003 | Microsoft Access 2002 2003 |
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