| ParameterModelReference | Represents a reference to parameter data in terms of a model. It does not have special logic |
| PropertyModelReference | Represents a reference to property data in terms of a model. |
| QueryContext | Represents context under which a query flow operates. |
| QueryExpressionContext | Represents context for a query expression that is used during query expression processing. |
| QueryModelReference | Represents a reference to query data in terms of a model. |
| DataSourceStubModelReference | Represents a reference to data source stub in terms of a model. |
| QueryRequest | Represents a query request. |
| QueryResult | Represents a query result. |