Normalizing To Boyce-Codd Normal Form

I am a big fan of Boyce-Codd Normal Form:

Boyce-Codd Normal Form is a generalization of Second and Third Normal Forms.  There are a couple of requirements to be in Boyce-Codd Normal Form.  First, your table must be in First Normal Form.  This means that:

  • Every entity (row) has a consistent shape.  This is something relational databases do for you automatically:  you can’t create a table where one entity has an attribute (column) but the next entity doesn’t.
  • Every entity has a unique value.  You can uniquely identify any particular row.
  • Every attribute is atomic:  you don’t try to pack more than one value into a single attribute.
  • There are no repeating groups of attributes, like PaymentMethod1, PaymentMethod2, PaymentMethod3, etc.

The other half of BCNF is that every determinant on an entity is a key.

Also click through for an iterative, easy-to-follow process to get to BCNF.

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