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E - R diagram how to draw, there are many relations

Time:09-15

Users can release goods can buy goods again, this kind of the relationship between the user and the goods how to draw?

CodePudding user response:

CodePudding user response:

No problem ah,
Release is issued, buying is to buy, the business is completely different, not conflict,
Just like liu can on their own, jingdong mall shopping

The users table
Commodity list (including release user UserId)
Order list (an order may have multiple items)
Order item table (including commodity Id)

CodePudding user response:

A typical many-to-many design,
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