Define the Armstrong rules

Question

Define the Armstrong rules.

Answer 1

The well-identified inference rules for FDs

• Reflexive rule:

X Y, if Y is subset or equal to X.

• Augmentation rule:

XZ YZ, if X Y.

• Transitive rule:

When {X Y, Y Z} then X Z.

• Decomposition rule:

When X YZ then X Y.

• Union or Additive rule:

When {X Y, X Z} then X YZ.

• Pseudo Transitive rule:

When {X Y, WY Z} then WX Z.