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Chapter 06
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20
Computer Science
Undergraduate 2
04/25/2011

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Term
Normalization
Definition
Process for evaluating and correcting table structures to reduce data anomalies, redundancies, and inconsistencies
Term
Normalization Stages
Definition
First Normal Form
Second Normal Form
Third Normal Form
BCNF
Fourth Normal Form
Fifth Normal Form
Domain Key Normal Form
Term
The higher the level...
Definition
The slower the database response
Term
Data redundancy leads to
Definition
Data inconsistencies
Wasted data entry time and storage space
Term
Anomalies
Definition
Abnormal data relationships
Term
Types of Anomalies
Definition
Insert anomaly
Update anomaly
Deletion anomaly
Term
Main source of data anomalies
Definition
Functional dependencies
Term
Normalization Process
Definition
Start with a big table
Break into a set of smaller tables that are related
Each table represents a single entity to eliminate data redundancies
Term
Repeating Groups
Definition
Groups of multiple entries of the same type that exist for any single key attribute occurrence
Cause null values
Term
A table is in 1NF when
Definition
No repeating groups, and the primary key is identified
Enter in values for all of the null values, then identify a primary key
Primary key can't have redundancies and must be an identifier of other columns
Draw a dependency diagram
Term
Partial Dependency
Definition
An attribute depends on only a portion of the primary key
Term
Transitive Dependency
Definition
Two none key attributes that depend on each other
Cause data anomalies
Term
How to convert table from 1NF to 2NF
Definition
Eliminate partial dependencies
Term
How to convert table from 2NF to 3NF
Definition
Eliminate transitive dependencies
Term
How to remove partial dependencies
Definition
Write each key component of a separate line
Write composite key on the last line
Assign dependent attributes
Term
Table is already in 2NF when
Definition
It is in 1NF
and includes no partial dependencies so the table has a single primary key
Term
When you remove a transitive dependency...
Definition
keep the determinant in the original table, otherwise you will lose that link
Term
BCNF
Definition
Every determinant in table is a candidate key
Term
Table is in 4NF when
Definition
It is is 2NF
And no multiple set of multi-valued dependencies
Term
Denormalization
Definition
Go from 3rd form to 2nd form to save time on queeries
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