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gdanelian
Starting Member
1 Post |
 Posted - 2008-11-21 : 04:41:40
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| Hello all! My ER Diagram has a many to many relationship between MEMBERS and GOLF CLUB. Many members can join more than one golf club. Many GOLF CLUBS have many MEMBERS. When mapping the relations this means that I need a table to express this m:n relationships. I want to create a table in SQL with the table name: BELONGSTO and the two columns will be the primary key from MEMBERS (member-no) and the primary key from GOLF CLUB (club-no) to create a composite key (member-no, club-no). How would I do this in SQL?ALL HELOP WELCOME, THANK YOU FOR YOUR TIMEG |
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visakh16
Very Important crosS Applying yaK Herder
52326 Posts |
Posted - 2008-11-21 : 04:47:08
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| If members can join more than one golfclub its better to kep a seperate identity column names belongs_to_id as primary key of relationship table belongs_to |
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visakh16
Very Important crosS Applying yaK Herder
52326 Posts |
Posted - 2008-11-21 : 04:55:24
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something like CREATE TABLE BELONGS_TO(Belongs_To_ID int identity(1,1) PRIMARY KEY CLUSTERED,club_no int REFERENCES GOLF_CLUB (club_no),member_no int REFERENCES MEMBERS (member_no)) |
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LoztInSpace
Aged Yak Warrior
940 Posts |
Posted - 2008-11-21 : 20:39:21
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| I would not have the identity and have the PK AS CLUB_NO and member_no.If you do decide to have the ID then at least put a unique and not null constraint on the 2 columns |
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Composite Key creation in SQL to refelct a n:m