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I wanted to know how to represent a relationship between two entities which means "atleast".

Eg- A song must be part of atleast one album.

If "A song can be part of one or more than one album" means a one to many relationship between song and album, then what would the ER diagram for the Eg given above be?

arijeet
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1 Answers1

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It's represented on an ERD by a double line (called a participation constraint).

If one song can be on many albums, you need a junction table, Like so:

album -+------< album_song >------+- song

Wil
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