DataBase System Relational model A Laid down in 1969-1970 by Ef.codd A Relational Model of data for large shared Data Bank C aCM 1970 Mathematical Bases( relational Theory) E Developed in 1980s t Most commercial dbms are relational Haichang Gao, Software School, Xidian UniversityDataBase System Haichang Gao , Software School , Xidian University 4 Relational Model Laid down in 1969-1970 by E.F.CODD “ A Relational Model of Data for Large Shared Data Bank” C ACM 1970  Mathematical Bases ( Relational Theory)  Developed in 1980s  Most commercial DBMS are Relational