Working with Entities in Model Designer
When you create a report model using the Report Model wizard, a collection of entities is automatically generated for you based on items in your database as described in your data source view (.dsv) file. An entity is a logical collection of model items, including source fields, roles, folders and expressions, presented in familiar business terms. For example, a Products entity might contain information, such as product name, product number, and list price, related to each of the products that your company manufactures. Most entities correspond to a table in the database, depending on which rules you selected in the Report Model wizard, but entities can contain model items that return data from more than one table.
To control the behavior of the entities within Report Builder, you can set the properties on the entities and the items within them using Model Designer. You determine such entity behavior as inheritance, instance selection, and sorting. For example, you can set the properties of one entity so that it inherits the attributes of another entity, or you set the behavior so that Report Builder users must use a filtered list to select data from within the entity instance. In addition, such model item behavior as alignment, formatting, and sort direction can be controlled. For example, if the attribute contains monetary data, you can format the data so that it is automatically formatted to the currency indicated by the culture. The Report Builder user doesn't have to format the data within the report.
Once you create the report model, you might want to refine the model to make it even easier for your users to use. By default, entities and folders are listed in alphabetical order, but you can rearrange them according to how you think your users will use the data in them to build reports. For example, if you think most of your Report Builder users will use the Products entity frequently you might want to move it to the top of the model items list.
If the underlying schema changes, you can create a new entity to reflect these changes in the model. When you create a new entity, you need to bind it to a table or column in the database using the Binding property. After the entity is bound to the database, you can add a role, source field, folder, or expression to the entity by right-clicking the entity.