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Relational database and keeping track of objects


arpowers

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hey everyone..

 

here is my question... when you are designing a relational database you have many different relations, is it better to assign a table to each 'type' of relation or to create a master relational table where all relations are defined.

For example:

rtbl_bananas_oranges

rtbl_bananas_pears

 

in contrast to:

 

rtbl_relations.. containing the columns

 

id(primarykey) .. object1_id.. object2_id

 

then go into object_id table and see what type it is..

 

....

 

the reason I ask is it gets tedious to keep track of an objects ID as well as its type ..

hopefully this makes sense, Im going crazy trying to figure out how to implement this..

 

Andrew

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You don't want to make a separate table specifying which field links to what in each of the other tables, that would get really confusing.

 

Just store what you have to store to create the relationship. Here is an example

 

TABLE customers       TABLE orders      TABLE items
----------------      --------------    ------------
customerID   +---+     orderID      +--  itemID
name             +--   customerID   |    name
address                itemID +-----+    price

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