Database Normalization

What is Database Normalization?

• Database normalization is the process of organizing the fields and tables of a database to minimize data redundancy and dependency.
• Normalization involves dividing large tables into smaller tables and linking them using relationships.

Types of Normalization

• First Normal Form (1NF): Each table cell must contain a single value.
• Second Normal Form (2NF): Each non-key attribute in a table must depend on the entire primary key.
• Third Normal Form (3NF): If a table is in 2NF, and a non-key attribute depends on another non-key attribute, then it should be moved to a separate table.
• Boyce-Codd Normal Form (BCNF): A table is in BCNF if and only if it is in 3NF and there are no transitive dependencies.
• Fourth Normal Form (4NF): A table is in 4NF if and only if it is in BCNF and there are no multi-level dependencies.
• Fifth Normal Form (5NF): A table is in 5NF if and only if it is in 4NF and there are no join dependencies.
• Domain-Key Normal Form (DKNF): A table is in DKNF if and only if each constraint on the table is a logical consequence of the definition of the table's keys and domains.

Benefits of Normalization

• Reduces data redundancy and inconsistencies
• Improves data integrity and accuracy
• Makes data easier to maintain and update
• Improves scalability and flexibility
• Reduces data anomalies and errors

Normalization Rules

• Eliminate repeating groups
• Eliminate partial dependencies
• Eliminate transitive dependencies
• Eliminate multi-level dependencies

Denormalization

• Denormalization is the process of intentionally violating normalization rules to improve performance.
• Denormalization is often used in data warehousing and online analytical processing (OLAP) systems.
• Denormalization can lead to data redundancy and inconsistencies, but can improve query performance.

What is Database Normalization?

• Database normalization is the process of organizing fields and tables to minimize data redundancy and dependency.
• It involves dividing large tables into smaller tables and linking them using relationships.

Types of Normalization

• First Normal Form (1NF): Each table cell must contain a single value.
• Second Normal Form (2NF): Each non-key attribute in a table must depend on the entire primary key.
• Third Normal Form (3NF): If a table is in 2NF, and a non-key attribute depends on another non-key attribute, then it should be moved to a separate table.
• Boyce-Codd Normal Form (BCNF): A table is in BCNF if and only if it is in 3NF and there are no transitive dependencies.
• Fourth Normal Form (4NF): A table is in 4NF if and only if it is in BCNF and there are no multi-level dependencies.
• Fifth Normal Form (5NF): A table is in 5NF if and only if it is in 4NF and there are no join dependencies.
• Domain-Key Normal Form (DKNF): A table is in DKNF if and only if each constraint on the table is a logical consequence of the definition of the table's keys and domains.

Benefits of Normalization

• Reduces data redundancy and inconsistencies.
• Improves data integrity and accuracy.
• Makes data easier to maintain and update.
• Improves scalability and flexibility.
• Reduces data anomalies and errors.

Normalization Rules

• Eliminate repeating groups.
• Eliminate partial dependencies.
• Eliminate transitive dependencies.
• Eliminate multi-level dependencies.

Denormalization

• Denormalization is the process of intentionally violating normalization rules to improve performance.
• Often used in data warehousing and online analytical processing (OLAP) systems.
• Can lead to data redundancy and inconsistencies, but can improve query performance.

What is Normalization?

• Normalization is the process of organizing data in a database to minimize data redundancy and dependency.

Goals of Normalization

• Eliminate data redundancy to avoid storing duplicate data.
• Reduce data duplication to prevent inconsistencies.
• Improve data integrity by ensuring data accuracy and consistency.
• Simplify data maintenance by making it easier to update or modify data.
• Improve scalability to handle large amounts of data.

Normal Forms

First Normal Form (1NF)

• Each table cell must contain a single value, no repeating groups or arrays.

Second Normal Form (2NF)

• Each non-key attribute in a table must depend on the entire primary key.

Third Normal Form (3NF)

• If a table is in 2NF, and a non-key attribute depends on another non-key attribute, then it should be moved to a separate table.

Rules of Normalization

• Eliminate Repeating Groups to ensure each row in a table has a unique combination of values.
• Eliminate Partial Dependencies to ensure a non-key attribute depends on the entire primary key.
• Eliminate Transitive Dependencies to ensure direct dependencies, avoiding intermediate dependencies.

Normalization Techniques

• Denormalization: intentionally denormalizing a database to improve performance, but may compromise data integrity.
• Vertical Partitioning: splitting a table into two tables, one with frequently accessed columns and one with infrequently accessed columns.
• Horizontal Partitioning: splitting a table into two tables, one with frequently accessed rows and one with infrequently accessed rows.

Benefits of Normalization

• Improved data integrity ensures data accuracy and consistency.
• Reduced data redundancy eliminates duplicate data and inconsistencies.
• Improved scalability enables handling large amounts of data.
• Improved data security ensures data is protected from unauthorized access.
• Improved data maintenance makes it easier to update or modify data.