Complete set of keywords that you need to know about normalization

Complete set of Important Keywords that you need to know about Normalization / Top keywords about normalization and normal forms / Define normalization / Define normal forms / Answer to all DEFINE questions in the area of Normalization / Complete set of Important Keywords that you need to know about Database Normalization / Attributes definition / Keys definition / Data redundancy and anomalies

Complete set of keywords that you need to know about Normalization

Normalization and Normal Forms – Click here to read more…. Normalization, Normal form, 1NF, 2NF, 3NF, BCNF, 4NF, 5NF, 6NF, DKNF

Attributes – Click here to read more…. Determinant, Atomic attribute, Non-key attribute, key attribute, prime attribute, non-prime attribute

Functional Dependency – Click here to read more…. Functional dependency, Full functional dependency, Partial dependency, Multi-valued dependency

Keys – Click here to read more…. Super key, Candidate key, Primary key

Data Redundancy and Anomalies – Click here to read more…. Data redundancy, Insertion anomaly, Deletion anomaly, Updation anomaly

 

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Types of attributes that you need to know in normalization process

Set of keywords about attributes used in Normalization process / Set of attributes that you need to know in Normalization process / Key and prime attributes in Normalization process / Non-key or Non-prime attributes in Normalization process

Set of attributes that you need to know in normalization process

Atomic Attribute – Click to read more… An attribute that stores single value (not multiple values separated by a comma or any other separators) for each record is called atomic attribute.

Determinant – Click to read more… A determinant in a database table is single or set of attributes that can be used to determine the values of other attributes (those that are dependent on the determinant attributes) uniquely. For example, consider a table Student with attributes Register_no, Name, and Date_of_Birth. Here, Register_No is a determinant that can uniquely identify the other set of attributes. In a functional dependency, the Left Hand Side (LHS) attribute is determinant.

Non-key Attribute – Click to read more… An attribute that is not a primary key attribute or part of a primary key (in case of composite primary keys) is called as non-key attribute.

Non-prime Attribute – Click to read more… Refer Non-key Attribute above.

Prime Attribute – Click to read more… In a composite primary key (or candidate key), the component attributes are called as prime attributes. For example, if you have (Register_No, Course_No) as the primary key (or candidate key) for your table, then Register_no is one prime attribute and the Course_no is the other.

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Important keywords about database normalization and normal forms

Important keywords about database normalization and normal forms / Define Normalization / Define Normal forms / Define 1NF, 2NF, 3NF etc./ What is normalization? / What is normal form?

Keywords that you need to know in Database normalization

Normalization – Click to read more… It is the process of organizing (or defining) the structure (the columns / attributes) of a relation (a table) in such a way to avoid data redundancy, and to avoid anomalies like insertion anomaly, deletion anomaly, and updation anomaly.

Normal Form – Click to read more… Normal form is one the several stages a table can be defined to avoid redundancy and anomalies. Each stage handles anomalies or redundancies that would be possible at that level. We have 1NF (First Normal Form), 2NF (Second Normal form), 3NF (Third Normal Form), BCNF (Boyce-Codd Normal Form), 4NF (Fourth Normal Form), 5NF (Fifth Normal Form / Project-Join Normal Form), 6NF (Sixth Normal Form), and DKNF (Domain-Key Normal Form – 3NF, BCNF, 4NF, and 5NF are special cases of DKNF). Each of these normal forms handles anomalies or redundancies at that level to give a better database design.

1NF / First Normal Form – Click to read more… It is one of the several stages a table can be in. We would say that the table is in 1NF if all the attributes are Atomic attributes.

2NF / Second Normal Form – Click to read more… It is one of the several stages a table can be in when the following properties are satisfied by the table in question; Relation (table) should be in 1NF Every non-key attribute should fully functionally dependent on the primary key or whole key (composite primary key) of the table.

3NF / Third Normal Form – Click to read more… It is one of the several stages a table can be in when the following properties are satisfied by the table in question; The table should be in 2NF Every non-key attribute of the table is non-transitively dependent on each candidate key of the table. In other words, no non-key attribute should depend on another non-key attribute.

BCNF / Boyce-Codd Normal Form – Click to read more… It is one of the several stages a table can be in when the following properties are satisfied by the table in question; The table should be in 3NF Every determinant should be a candidate key. (i.e., every Left Hand Side (LHS) of a functional dependency should be a candidate key)

4NF / Fourth Normal Form – Click to read more…

5NF / Fifth Normal Form – Click to read more…

6NF / Sixth Normal Form – Click to read more…

DKNF / Domain-Key Normal Form – Click to read more…

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Normalization solved exercise to find key

Set of solved exercises in Normalization / Normalization Solved Examples / How to find candidate keys, and primary keys in database? / Sets of examples to find the keys of a tables / Process of Key finding in a database – Examples.

Question:

Consider a relation R (A, B, C, D) with FD's B → C, D → A. Determine all the keys of relation R. 

Solution:

To find the key of a relation, we need to find the closure of attributes. If any attribute’s or set of attributes’ closure gives all the attributes of the relation, then we would say that attribute/set of attributes as the key for that relation.

To simplify this task or to avoid finding closure of all attributes, let us do find the closure for left hand side (LHS) attributes of the functional dependencies.

For the given question, attributes B and D are the LHS attributes.

• The closure of B, (B)⁺ = BC from ≠ ABCD. Hence B is not a key. [Refer, How tofind closure/how to find key, purpose of finding attribute closure]

• The closure of D, (D)⁺ = DA ≠ ABCD. Hence D is not a key. [Refer, How to find closure/how to find key, purpose of finding attribute closure]

• The closure of B and D together, i.e., (BD)⁺ = ABCD. All the attributes can be determined. Hence, BD is a key (a composite key).

 The key for R is (BD).


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Normalization process solved problems

Important normalization exercises solved an explained

How to find the key of a relation during normalization process