Designing the Database
This step overlaps considerably with understanding the business requirements. Throughout that process, we draw rough data models showing the relationships involved and make lists of field names.

DataModel.jpgThe data model is the important side of the database design. It covers the data tables, the fields in those tables and the relationships between the tables. If the business anaylsis is done correctly then the data model will be correct; and if that's correct, then the forms will make sense to the users. Viewing any existing data will help this process. Field sizes, compulsory fields, lookup lists, field names: are all important to get right at this stage.

We use the following standards in designing the database:
• primary keys on all tables, but not necessarily AutoNumber fields
• referential integrity with cascading updates on all relationships, plus cascading deletes where appropriate [more details..]
• no spaces or underscores in table or field names
• table names in pural form
• meaningful field names - usually limited to 15 characters
• no prefixes for datatypes on field names
• no prefixes on MS Access object names (tables, queries, etc)
• show all tables on the data model even if they have no relationships
From the data model and the business requirements come the application structure. This covers menus, forms, subforms and any special processing. A 2 level menu structure is designed based on the Client's business functions. Usually, for each table there is a form; and for each relationship a table has, there is a subform. E.g. If the 'Plant Items' table has relationships to the 'Plant Audits' table and to the 'Plant Locations' table; then the Plant Items form has subforms for Audits and Locations on seprate tabs.

If MS Access security is required, the user groups and their permissions need to be discussed (but not set in concrete) at this stage.

A meeting is held with the Client to explain the data model and the application structure. If this meeting is successful, then the development starts.

The next step in developing applications is Developing and Implementing.

 

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