relationship : My stupid question...
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Len Boorman
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You cannot have a many to many.
If you need to change relationships then I suggest that there is a design problem with your database. In the best regulated world relationships are one to many with referential integrity enforced. One to One do occurr but rarely.
L
If you need to change relationships then I suggest that there is a design problem with your database. In the best regulated world relationships are one to many with referential integrity enforced. One to One do occurr but rarely.
L
Len Boorman said:
so, how bout this...
1 customer can buy many parts at once...
and 1 part can be bought by many customers..
at my relation that i create , only part have many customer but not for customer....help me plz..
Len Boorman
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Customer to Parts is M:M
Parts to Customer is M:M
Therefore you decompose with an intermediate table
New Table is CustomerParts
Take PK from each participating table to form PK in New table.
Customer to CustomerParts is 1:M
Parts to CustomerParts is 1:M
This is not the end however. I suspect that you will need additional fields in the new table. Maybe Order Ref, Qty etc. The new table may effectively your order table
Len
Len
Parts to Customer is M:M
Therefore you decompose with an intermediate table
New Table is CustomerParts
Take PK from each participating table to form PK in New table.
Customer to CustomerParts is 1:M
Parts to CustomerParts is 1:M
This is not the end however. I suspect that you will need additional fields in the new table. Maybe Order Ref, Qty etc. The new table may effectively your order table
Len
Len
neileg
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The relationship between the dat is not determined by Access, it's a question of fact. By choosing where to hold the foreign keys determines how Access views the relationship, but the only thing you change change, really, is the join.
When Les says you can't have a many to many relationship, he means that simply having two joined tables will not model this. As he says, you need a third table, usually called a junction table, to implement a m:m relationship in your database.
When Les says you can't have a many to many relationship, he means that simply having two joined tables will not model this. As he says, you need a third table, usually called a junction table, to implement a m:m relationship in your database.
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