The paper presents a Construction Database Model (CDM) used for the conceptual level modeling of design objects. A primary intention of the CDM model is modeling hierarchically structured objects and construction dependencies among objects. CDM is an attribute based data model. The CDM model represents various abstractions identified in the semantic database models GSM, IFO, SAM* and FDM by means of attributes. To distinguish between different abstractions, the notion of attribute role is introduced. Special attention is paid to the representation of derived properties of the object. They are described by means of a constructor, that can be compared to derived attributes as defined in Cactis, Trait, FDM and SDM data models. The constructor enables the description and reevaluation of the design object construction process. The CDM is used as a data model for the storage system Cons-Base, designed for storing data in CAD applications.