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Databases Querying Relational Databases Table Relationships One to Many Relationships

Leigh Maher
Leigh Maher
21,830 Points
Posted by Leigh Maher
Leigh Maher
21,830 Points

Is it realistic for this relationship to be one-to-many?

I may be misunderstanding this but I'm just thinking that orders often contain more than one product, in which case an order can contain many products. But and order ID has to be unique so there would need to be a joining table that would take care of all of the lines on an order? The order_line table would contain: Order_ID, Product_ID, and maybe add some fields that could be unique to the order line, like size (assuming sizes are attributes and not unique product_ID's) or quantity?

2 Answers

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

For the example shown in the video, the instructor defines this limit on the data: "...a Sale has 1 product...".

But your suggestion would fit a more typical real-world scenario; and then yes, an intermediate table to associate multiple products with each Sale would make sense.

Leigh Maher
Leigh Maher
21,830 Points
Leigh Maher
Leigh Maher
21,830 Points

Thanks Steven. I understand now. I had thought that he was saying this as a matter of fact rather than setting limits on the relationship for the sake of making the example work. Would have been good to have seen a real world (realistic) example, as I still get confused by these relationships sometimes.