Abstract: In this paper,we use the combinative method of relation model,graph grammar and the object-oriented style to model the definition of data and the processing of data which are represented in a unified tree graph structure.The tree graph grammar of the generating local extended entity relation (EE-R) diagrams,the merging EE-R diagram and the modified history or transaction editions of database are proposed.The assistant tool of the concept design of database “LEARNER” is proposed and implemented for the personnel of application exploitation-oriented and the students who learn the databases.LEARNER provides to create the concept schema,subschema and the history and transaction editions of databases that are required for them.