Object-relational databases use the concept of relational database along with object oriented approach. It is a blend of the traditional relational database with ability to handle objects. It is used for handling large documents based data and multimedia content. Here are the features of Object-relational database:
1) They use large data objects to store audio, video, web pages, etc.
2) Apart from the regular data types an object-relational databases use user defined data types.
3) They use structured and abstract data types.
4) In a object-relational database entire table can be put within a table. A column can contain complex structured data items.
5) Data items can be in the form of sets, sequences and arrays.
6) An object-relational database uses stored procedures.
7) It uses unique identifiers for objects like row id.