Data Dictionaries

NOTE: new content has been added to DataDictionary. TODO: merge the two pages

Data Dictionaries are a class layer between your application and the database tables. They are considered to be a vital part of any Dataflex development.

The Database Builder tool helps you defining the class with visual aid for:

• Field settings like Capslock
• Table settings like calculations on save or save/delete validations
• Relationship settings like Cascade Delete.

The Datadictionary class can also contain and business rules required when records are created, edited or deleted.

How to create a new Data Dictionary from scratch

1. Open Database Builder.
2. Create a new table
3. Enter some columns (input name, type and width)
4. Choose Maintenance and Create Empty DataDictionary.

NOTE: remember to enter a width for your column.

How to create Relationships

Before creating relationships, make sure that both tables should have an index.

• use 'the relationship wizard' in the database builder.

Use Data Dictionaries in Batch Processes

When using the studio, the usage of Data Dictionaries are very naturally integrated into your project. But when doing a save without dbForm objects eg in a batch process or so, a lot of developers are going back to the file buffer way. This way it bypasses the class structure you carefully put in place for saves, deletes, updates etc. Please check Using Data Dictionaries in Business Processes for help and sample code.

Supported backends

It is possible to reach several databases through the Data Access DataFlex Connectivity Kit or using third party drivers from Mertech Data [1]

• Native DataFlex database
• Oracle [2]
• Microsoft SQL Server [3]
• Pervasive SQL
• ODBC
• MySQL
• IBM DB2