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Flashcards in Function Dependencies & Normalization Deck (19):
1

Types of update anomalies

Insertion, Deletion, Modification

2

Functional Dependencies

Given X->Y, the attributes X will determine the attributes Y uniquely.

Y is functionally dependent on X
X functionally determines Y

3

Full functional dependencies

Given X->Y, there can be no attributes taken out of X such that X can still determine Y

4

1NF

All domain values in R are atomic.

In other words, no nested values, lists of attributes etc.

5

2NF

R is in 1NF AND every non-key attribute if fully dependent on the primary key.

In other words, each non-candidate key needs to be only identified by the entire primary key, not just part of it.

6

3NF

R is in 2NF AND every non-key attribute is non-transitively dependent on the primary key.

In other words, there are not any attributes that depend on the status of other non-prime attributes

7

BCNF

Boyce-Codd Normal Form:

Every functional dependency of the relation, R, is determined by primary key(s) only.

8

Superkey

Attributes that uniquely identity a tuple

9

Key

A minimal superkey

10

Candidate Key

A key that could uniquely identity a relation

11

Alternate key

A secondary key that could have been the primary key

12

Foreign key

A key that maps to another entity

13

Natural Key

Keys that exist in the real world, ssn,

14

Composite key

Keys with two or more attributes

15

Surrogate Key

Key with no real world meaning, opposite of a natural key

16

Surrogate Key VS Natural Key

When choosing a Primary Key it is best to use a natural key.

17

Non-loss decomposition

When a relation is decomposed, can it be composed again without loss of any data.

18

4NF

When a relation has multi-valued dependancies

19

5NF

When a relation has join dependencies