Normalization Flashcards
(27 cards)
a process of organizing data to minimize data redundancy, a series of steps taken to remove redundancy and update anomalies in database design.
Normalization
It main objective is to create an accurate
representation of data, its relationship, and constraints.
Purpose of Normalization
Facilitate the ______ and ______________ of data to users and applications that make use of the databases
access and interpretation
Goal #1
TWO MAIN GOALS OF NORMALIZATION
Eliminate redundancy of data.
Goal #2
TWO MAIN GOALS OF NORMALIZATION
Eliminate insert, delete, and
update anomalies.
disallowing multivalued attributes
three main rules for normalizing data
Eliminate repeating data
no column in the table can be related only to a part of the primary key
three main rules for normalizing data
Eliminate partial dependencies
a column in the table refers to a non-key column instead of referring to the primary key of a table.
three main rules for normalizing data
Eliminate transitive dependencies
It describes the relationship between
attributes (column) in a table.
Functional Dependency
- An attribute or a group of attributes
on the left-hand side of the arrow of a
functional dependency
Functional Dependency
determinant
B is functionally dependent on A but not on any proper subsets of A
Functional Dependency
A and B are attributes (columns) in a table
Full Functional Dependency
Some attributes can be removed from A but the dependency still holds.
Functional Dependency
A and B are attributes (columns) in a table
Partial Functional Dependency
if A is functionally dependent on B, and B is functionally dependent on C and C is ________ dependent on A via B.
Functional Dependency
A, B and C are attributes (columns) in a table
Transitive Functional Dependency
A table that consists of one or more repeating groups.
Process of Normalization
Unnormalized Form
the domain of an attribute must include only atomic values and that the value of any attribute in a tuple must be a single value from the domain of that attribute.
Process of Normalization
First Normal Form (1NF)
It is in this form IF and only IF it is in 1NF and every non-key attribute is fully dependent on the primary key.
Process of Normalization
It is accomplished by eliminating partial dependencies.
Second Normal Form (1NF)
It is in this for IF and only IF it is in 2NF and every non-key attribute is nontransitively (or directly) dependent on the primary key.
Process of Normalization
Third Normal Form (1NF)
a slightly stronger version of the third normal form. It handles a problem with an entity that might have two primary keys.
Process of Normalization: Higher Level of Normal Forms
The Boyce-Codd Normal Form (BCNF)
It is in this form IF and only IF every join dependency in the relation is a consequence of the candidate keys of the relation
Process of Normalization: Higher Level of Normal Forms
also called the projection-join normal form (PJ/NF).
The Fifth Normal Form (5NF)
a key that uniquely identifies rows in a table. It can be a combination of attributes that can be
uniquely used to identify a database record without any extraneous data.
candidate key
This normal form was named after Ray Boyce who was one of the creators of SQL, and Edgar Codd
who is the father of relational databases.
The Boyce-Codd Normal Form (BCNF)
It eliminates most of the anomalies known in databases today, and it is the most common
standard for normalization in commercial databases and computer-aided software engineering
tools.
The Boyce-Codd Normal Form (BCNF)
Correct duplicate ____ and database _________
data, anomalies
Avoid ________ and ________ any unwanted data connections and dependencies.
creating and updating
