8000 Deal with the "FK can not be a (part of a) PK" issue · Issue #7 · fuelphp-storage/orm · GitHub
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Deal with the "FK can not be a (part of a) PK" issue #7

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WanWizard opened this issue Aug 23, 2013 · 3 comments
Open

Deal with the "FK can not be a (part of a) PK" issue #7

WanWizard opened this issue Aug 23, 2013 · 3 comments

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@WanWizard
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No description provided.

@emlynwest
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How do we handle this? We can either leave it as it is currently and make a note that you should not be using a FK as a PK in your DBMS or we do not update the FK on changes to the relation. The both could cause issues, the latter especially so as it might lead some items to become "re-related" to new parent models.

@WanWizard
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From the database and/or normalisation point of view this is not a problem, but there are some restrictions to what you can do with it.

Consider:

  • table A, PK columnA
  • table B, PK columnB
  • table C, compound PK (columnA, columnB)
  • one-to-many between C and A, and between C and B

This should be possible, but may require a forced cascade-delete (in v1 terms), since you can not allow one of the table C PK columns to become NULL.

@emlynwest
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Ah I see, so it's making sure the database stays consistent with what is actually happening when relations are changed.

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@WanWizard @emlynwest
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