relationshiperd

Drawing Relationships In Entity Relationship Diagram


I used Azure to create a database. I used Azure Data Studio and https://github.com/R0tenur/visualization to create the following Entity Relationship Diagram / Relational Model (?). Are the relationships drawn correctly or reversed? Is it correct to read one relationship as "Between one and one course has between one and many outcomes."?

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Solution

  • The relationships seem indeed inverted: this diagram tells that:

    The cardinality symbol on the side of the outcomes tells how many outcomes can be related to one element of the opposite side, and vice-versa. The element closest to a table can be a bar (one) or a trident (many). The element next to it tells about the participation, which is either a bar (mandatory) or a circle (optional).

    The foreign keys in your tables confirm that the other relationships are also inverted.

    Here a link with more explanations on the crow's foot ERD notation and of course wikipedia.