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    Access, File Extensions

Throughout the years, Access has utilized many file extensions, each with it's own specific usage and meaning. The following is an explanation of each type.

MDB

A typical Access database file for Access versions 2003 and prior.

• If the file is being used as a typical backend), it will contain only Tables and Relationships.
• If the file is being used as a typical frontend), it will contain only Queries, Forms, Reports, Macros, and/or Modules.
• If the file is being used as a typical all-encompasing single-file database, it will contain all or any of the above.

MDE

A compiled MDB file.

This is accomplished by choosing Tools> Database Utilities> Make MDE File... from the File Menu.

When a database is compiled into an MDE, the ability to edit Forms, Reports, and Modules not longer exists. Some choose this option to further secure their database and prevent modification. The MDB file is kept in a safe place for further development, while only the MDE is distributed to the client.

A compiled database also needs top-notch error handling, as there is no ability to debug code.

MDA

An Access Add-In file.

This type of file may be used to collectively manage commonly used functions or procedures that can be accessed from many different databases.

MDW

An Access WorkGroup file.

This file is used in conjunction with Access' native User Level Security to manage permissions to database objects.

LDB

An Access Locking database file used with MDB/E format databases.

This file is used to manage concurrency while the database is in use. After all users exit the database, the LDB file should self-delete. If it does not, this may indicate that more user permissions are required to the directory (specifically Delete permissions).

ACCDB

A typical Access database file for Access versions 2007 and later.

ACCDE

A compiled ACCDB file.

This is accomplished by choosing Database Tools> Make ACCDE.

When a database is compiled, the ability to edit Forms, Reports, and Modules not longer exists. Some choose this option to further secure their database and prevent modification, keeping the ACCDB file safe, while only distributing the ACCDE.

ACCDR

This file extension indicates that Access should run in runtime mode, which disables the design modes and treat the file more like an application. The extension of an ACCDB is manually changed to ACCDR.

LACCDB

An Access Locking database file used with ACCDB/E/R format databases.

ADP

An Access Data Project.

This file extension is used when a special format of Access is being used as a frontend to SQL Server. The default internal database of Access (Jet) is not longer accessible, so there are no local Access Tables, Relationships, or Queries. They are replaced with SQL Server Tables, Relationship Diagrams, Views, and Stored Procedures.

ADE

A compiled ADP file.