How to apply the third normal form
The accounts payable system in second normal form
Questions about the structure
- Does the vendor information (vendorName, vendorAddress, etc.) depend only on the invoiceID column?
- Does the terms column depend only on the invoiceID column?
- Does the accountNo column depend only on the invoiceID column?
- Can the invoiceDueDate and lineItemAmount columns be derived from other data?
The accounts payable system in third normal form
Description
- For a table to be in third normal form, every non-key column must depend only on the primary key.
- If a column doesn’t depend only on the primary key, it implies that the column is assigned to the wrong table or that it can be computed from other columns in the table. A column that can be computed from other columns contains derived data.
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