Visual Basic Programmer

Microsoft Access Database Programmer

Microsoft Access Forms – Bound or Unbound?

Microsoft Access is designed for rapid application development. A form wizard allows fast and easy application development using Bound forms. The Bound form requires little or no programming, and is ideal for the amateur programmer.

Unbound forms require Visual Basic code to retrieve and update records. The Microsoft Access form can have a mixture of fields that are Bound or Unbound.

The Bound Form

The Bound form has bound fields that are linked directly to the database. Any changes made to a bound field are immediately updated in the corresponding field of the current record of a Table.

The features of the Bound form include:

• Quick set up time
• Find, Filter or Sort facility
• Record number and a navigation bar
• Spell Checking
• Selecting, adding, deleting or modifying records

The drawbacks of the Bound Form

Access applications have a habit of growing in size and complexity. In order to add features to the Bound form, the logic can soon become complex. Some problems:

• The default behaviour of Access may be unacceptable – such as automatically saving fields or records
• There are performance issues when manipulating data from the Back-End Database
• There is the need to explicitly control record locking
• Error messages are not user friendly
• Validation involving multiple fields is not user friendly
• Cancellation of an update with the Esc key is not user friendly
• It will be difficult to convert to VB.Net
• It is difficult to extract the business rules from the form logic

The Unbound Form

The Unbound form provides a better and more professional solution. It is needed for greater efficiency, to extend user numbers and to provide better control of the application. The Unbound form involves the use of VBA (Visual Basic for Applications) and ADO (ActiveX Data Objects).

The advantages of the Unbound form are:

• Greater control in reading and writing of records
• Records are updated only when all fields are valid
• User friendly error handling
• Efficiency in accessing records
• Elimination of concurrency issues
• Control of saving and deleting records
• Data integrity.
• The Unbound Form is easily converted to a VB.Net project