The ER Model is focussed to be a description of real-world entities. Although its development/construction is done in such a way as to allow fair and easy translation to the relational schema model, this is not fully trivial process. The ER diagram represents the conceptual level of database design while the relational schema represents the logical level for the database design. Following simple rules are followed: ADDRESS( cityAddress, city, state ) candidate key:cityAddress, city , state PERSON( pid,name ) candidate key: pid OBSERVATION (oid, date, temperature, humidity, precip. ,city), candidate key: oid foreign key: city OBSERVER ( pid ), candidate key: pid METEREOLOGIST( pid ), candidate key: pid CONSUMER( pid ), candidate key: pid WARNINGS( wwid,description,date,city) candidate key: wwid FORECAST( fid,city,date,low,high) candidate key: fid WEATHERPROGRAM( wid,name ) candidatekey; wid LIVESAT(city, streerAddress, state,pid) RECORDS(oid,pid,method) ISSUES(wwid.pid) PRESENTS(fid,pid) VIEWS(pid,fid) MAKES(wid,fid,oid) 15 tables will be created in all along with relationship tables and only 9 tables if relationships are shown as foreign keys Solution The ER Model is focussed to be a description of real-world entities. Although its development/construction is done in such a way as to allow fair and easy translation to the relational schema model, this is not fully trivial process. The ER diagram represents the conceptual level of database design while the relational schema represents the logical level for the database design. Following simple rules are followed: ADDRESS( cityAddress, city, state ) candidate key:cityAddress, city , state PERSON( pid,name ) candidate key: pid OBSERVATION (oid, date, temperature, humidity, precip. ,city), candidate key: oid foreign key: city OBSERVER ( pid ), candidate key: pid METEREOLOGIST( pid ), candidate key: pid CONSUMER( pid ), candidate key: pid WARNINGS( wwid,description,date,city) candidate key: wwid FORECAST( fid,city,date,low,high) candidate key: fid WEATHERPROGRAM( wid,name ) candidatekey; wid LIVESAT(city, streerAddress, state,pid) RECORDS(oid,pid,method) ISSUES(wwid.pid) PRESENTS(fid,pid) VIEWS(pid,fid) MAKES(wid,fid,oid) 15 tables will be created in all along with relationship tables and only 9 tables if relationships are shown as foreign keys.