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I want to clarify my diagram that I have created; ER diagram

I was wondering what I have made means the following things; 

- A company can book multiples jobs
- A company MUST own a job for it to exist

Am I correct in those assumptions from my diagram or have I done something wrong?

has400
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  • I've never seen anyone use a semicircle at the end of a role line before, so I can't even guess at the meaning. Note that meaning depends on agreement between author and reader, it's not inherent in any notation. If you want to make your meaning clear, include a legend to explain your notation. – reaanb Mar 28 '18 at 20:36
  • I know this is a very weird way of doing ER diagrams but the teachers said it is Referential Integrity @reaanb – has400 Mar 29 '18 at 01:09
  • Referential integrity means there's a subset constraint between two columns to ensure they represent the same domain. In an ERD, we don't have multiple columns of the same domain, instead those domains are directly represented as entity sets. – reaanb Mar 29 '18 at 04:25

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