The report model is the metadata layer component that serves as the basis for building reports. Report designers, both end users and IT staff, will use the report model as the data source for the report instead of directly accessing a relational database or OLAP cube data source when designing reports.
The report model contains three key elements necessary for the ad hoc reporting process to function smoothly: bindings to the underlying data-source schema, a logical representation of the schema in the form of business entities that are familiar to end users, and the default information to be used according to the role that the entity plays in the report (primary entity, lookup entity, summary, and so on).
A report model definition is an XML file that follows the Semantic Model Definition Language (SMDL) specification. Therefore, report models are also referred to as semantic models, SMDL, or SMDL models.
Report Model Components
Report models primarily consist of the following three item types:
- Entities are the equivalent of objects or tables in a database. Entities are composed of attributes and roles.
- Attributes are the equivalent of object properties or columns in a database table.
- Roles are the equivalent of object references or relational foreign keys and join operations.