8. What problems do object-oriented designs cause in a relational database model and how do you compensate for them?
The biggest problems arise from inheritance relationships. Subtables can be used in some DBMSs, but they are difficult to use. Generally, inherited data is either stored in separate tables using the same primary key, or merged into one table. The choice depends on the degree of overlap and number of attributes, along with the complications of handling the user interface.