As databases become increasingly complicated, building data warehouse with object concepts becomes the essential trend in the future. Designing such a data warehouse usually requires much human involvement. This work proposes a conceptual model for designing an object-relational data warehouse, and provides a semi-automated methodology for deriving the model from the standard documentation of the object-relational database. The construction of the model using the semi-automated methodology is demonstrated in simple examples. Furthermore, this work contributes a mapping mechanism from the conceptual schema to the logical design, and displays the mapping result in both a logical diagram and physical code. The physical code generated based on the logical diagram is refined by using the domain properties in object-relational database to improve the storage cost as well as query performance.