Data Design

EAV: Entity-Attribute-Value

OTLT: One True Lookup Table

Normalization

Normalize until it hurts; denormalize until it works

Ref:

Data Anomaly:

  • Update Anomalies
  • Insertion Anomalies
  • Deletion Anomalies

1NF:

  • no duplicated rows
  • each cell is single-valued (no repeating group or arrays)
  • entries in a column (field) are the same kind

2NF:

  • no partial functional dependency

3NF:

  • no partial transitive dependency (A -> B, B -> C, C is transitive depend to A)