Term
| Armstrong's Reflexivity Rule |
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Definition
| Given set of attributes X and Y are subsets of X, then X --> Y |
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Term
| Armstrong's Augmentation Rule |
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Definition
| If X --> Y , and Z is a set of attributes, then XZ --> Y Z. Also, this means that if X --> Y , then XZ --> Y ) |
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Term
| Armstrong's Transitivity Rule |
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Definition
| If X --> Y, and Y --> Z, then X --> Z |
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Term
| Union Rule (Supplemental) |
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Definition
| If X --> Y and X --> Z, then X --> YZ |
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Term
| Decomposition Rule (Supplemental) |
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Definition
| If X --> YZ, then X --> Y and X --> Z |
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Term
| Pseudo-transitivity Rule (Supplemental) |
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Definition
| If X --> Y and YW --> Z, then XW --> Z |
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Term
| Notation for Closure of a set of FDs 'F' |
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Definition
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Term
| Algorithm for Determining Closure of X+ under set of FDs F |
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Definition
X+ ← X
do {
oldX+ ← X+
for (each Y → Z EXISTS IN F)
if (Y SUBSET OF X+)
X+ ← X+ UNION Z
} until (oldX+ = X+) |
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Term
| Symbology for Fully Functional Dependency |
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Definition
-/->
Single arrow with slash from bottom left to top right |
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