Data types are essential design objects in CBA. They define

• the value range of attributes
• the saving format of values
• the lexis of possible inputs
• the validation routines
• the possibilities of operator guidance
• the available layouts for presentation in interfaces

on the basis of the assigned base type.

Data types are freely configurable and are oriantened on context-based criteria. They present concrete definitions of sets, that means defining explicit allowed and not allowed values. The sets can be defined

• implicit via the value range of the underlying base type
• explicit via a statement of minimal an maximal values
• explicit via a listing of allowed elements
• explicit via Regular Expression or Masking

Via the data types information for presenting in userinterfaces and for valditaion are derived. They present a powerful tool for configuration of attributes in tables and have an effect far beyond this. Values for attributes are checked for compliance with the underlying data type at e.g. the input in a userinterface or the saving in the database. This way it structurally results in a good controllability of the datas' validity. Data types cannot valdiate logical connections and semantic meaning - they are a pure formal mean. If logical connections and semantic meanings are to be validated, corresponding validating routines have to be integrated into Business Logic Units (BLU).

Base types are predefined, oriented on the IT-technical implementation and are the basis for defining logical data types. Base types represent data types in programs and databases, but also define different Layouts and ways for operator guidance in userinterfaces. The configuration, the validation, the formatting possibilites among others are dependent on base types. In CBA there are the following predefined base types:

Implicit data types are logical data types, that do not have to be defined explicitly. Every table generates a implicit data type with base type reference and the table's name in square brackets '[…]' as a data type name automatically. This way the data in the tables are available automatically. If special filters or sortings should be used, a explicit data type has to be defined.

Implicit data types are available at selection of a data type for an attribute, but are not visible in the userinterface for the data type.