関連ワード:  what is relational data in dbms    what is relational databases in dbms    what is relational data model in dbms    what is relational data integrity in dbms    what is relational data structure in dbms    what is relational data in database    what is object relational data model in dbms    what is relational data model in database    what is relational database design in dbms    what is relational database model in dbms