Thread: What is MDE
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Old August 24th, 2004, 04:28 AM
Raghu Prakash
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Hi Charlie,

If your database contains Microsoft Visual Basic for Applications (VBA)
(Visual Basic for Applications (VBA): A macro-language version of Microsoft
Visual Basic that is used to program Windows applications and is included
with several Microsoft applications.) code, saving your Microsoft Access
database (database: A collection of data related to a particular subject or
purpose. Within a database, information about a particular entity, such as
an employee or order, is categorized into tables, records, and fields.) as
an MDE file compiles all modules, removes all editable source code, and
compacts the destination database. Your Visual Basic code will continue to
run, but it cannot be viewed or edited. Your database will continue to
function as it did — you can still update data and run reports.

Saving your Access database as an MDE file does not prevent changes to the
database design. However, you will notice the following:

The user interface for modifying or creating forms, reports, or modules
will be disabled.
The VBA References dialog box will not allow adding, deleting, or changing
references to object libraries or databases.
The source code will not be available.
The importing and exporting commands will be disabled for forms, reports,
or modules. However, tables, queries, data access pages, and macros can be
imported from or exported to non-MDE databases.
Considerations if you need to modify the design of forms, reports, or
modules

Be sure to keep a copy of your original Access database. If you need to
modify the design of forms, reports, or modules in an MDE file, you must
modify the original Access database, and then resave it as an MDE file.
Saving an Access database containing tables as an MDE file creates
complications reconciling different versions of the data if you need to
modify the design of the forms, reports, or modules at a later date. For
this reason, saving an Access database as an MDE file is most appropriate
for the front-end database of a front-end/back-end application
(front-end/back-end application: An application consisting of a "back-end"
database file that contains tables, and copies of a "front-end" database
file that contain all other database objects with links to the "back-end"
tables.).

Code no longer employs user-level security

In previous versions of Access, user-level security could be used with VBA
modules. In Microsoft Access 2000 and later, all Visual Basic code for an
Access database (.mdb) file or an Access project (.adp) (Microsoft Access
project: An Access file that connects to a Microsoft SQL Server database
and is used to create client/server applications. A project file doesn't
contain any data or data-definition-based objects such as tables and
views.) file, including stand-alone modules (standard module: A module in
which you can place Sub and Function procedures that you want to be
available to other procedures throughout your database.) and class modules
(class module: A module that can contain the definition for a new object.
Each instance of a class creates a new object. Procedures defined in the
module become properties and methods of the object. Class modules can exist
alone or with forms and reports.) (such as code behind forms and reports),
must employ security technologies, such as setting a password, or by saving
the database as an MDE or ADE file, which removes the source code.

Considerations before saving your database as an MDE file

Some restrictions may prevent you from saving your Access database as an
MDE file:

You must have password access to the Visual Basic code.
If your database is replicated, you must first remove replication
(replication: The process of copying a database so that two or more copies
can exchange updates of data or replicated objects. This exchange is called
synchronization.).
If your Access database references another Access database, or add-in
(add-in: A supplemental program that adds custom commands or custom
features to Microsoft Office.), you must save all Access databases or
add-ins in the chain of references as MDE files.
Additionally, if you define a database password or user-level security
before saving an Access database as an MDE file, those features will still
apply to an MDE file created from that database. If your Access database
has a database password or user-level security defined, and you want to
remove these features, you must do so before saving it as an MDE file.

To save an Access database that employs user-level security as an MDE file,
you must meet the following requirements before you can proceed:

You must join the workgroup (workgroup information file: A file that Access
reads at startup that contains information about the users in a workgroup.
This information includes users' account names, their passwords, and the
groups of which they are members.) that defines the user accounts used to
access the database, or that were in use when the database was created.
Your user account must have Open/Run and Open Exclusive permissions for the
database.
Your user account must have Modify Design or Administer permissions for any
tables in the database, or you must be the owner (owner: When security is
being used, the user account that has control over a database or database
object. By default, the user account that created a database or database
object is the owner.) of any tables in the database.
Your user account must have Read Design permissions for all objects in the
database.
About references and MDE files

If you try to create an MDE file from a Microsoft Access database (.mdb) or
an add-in (.mda) (add-in: A supplemental program that adds custom commands
or custom features to Microsoft Office.) that references another Access
database or add-in, Access displays an error message and doesn't let you
complete the operation. To save a database that references another database
as an MDE file, you must save all databases in the chain of references as
MDE files, starting from the first database referenced. After saving the
first database as an MDE file, you must then update the reference in the
next database to point to the new MDE file before saving it as an MDE file,
and so on.

For example, if Database1.mdb references Database2.mdb, which references
Database3.mda, you would proceed as follows:

Save Database3.mda as Database3.mde.
Open Database 2.mdb, and change its reference to point to the new
Database3.mde.
Save Database2.mdb as Database2.mde.
Open Database1.mdb, and change its reference to point to the new
Database2.mde.
Save Database1.mdb as Database1.mde.
About saving a replicated database as an MDE file

A replicated database (either a replica (replica: A copy of a database that
is a member of a replica set and can be synchronized with other replicas in
the set. Changes to the data in a replicated table in one replica are sent
and applied to the other replicas.) or Design Master (Design Master: The
only member of the replica set in which you can make changes to the
database structure that can be propagated to other replicas.)) cannot be
saved as an MDE file. To save a replicated database as an MDE file, you
must first remove replication (replication: The process of copying a
database so that two or more copies can exchange updates of data or
replicated objects. This exchange is called synchronization.).

Once a database is saved as an MDE file, it can be replicated; however,
replication is only recommended in situations where no further changes need
to be made to the original database. If you need to make a design change to
a replica set (replica set: The Design Master and all replicas that share
the same database design and unique replica set identifier.) of MDE files,
you must make that change in the original database, resave it as an MDE
file, and then create and distribute an entirely new replica set from the
new MDE file.


For Further Informations:
http://office.microsoft.com/assistan...052393021033&C
TT=98

Please let me know has this helped You...
Thank you...
Raghu...
This posting is provided "AS IS" with no warranties, and confers no rights.