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Questions and Answers
What is the primary goal of database normalization?
What is the primary goal of database normalization?
Which normal form states that each non-key attribute in a table must depend on the entire primary key?
Which normal form states that each non-key attribute in a table must depend on the entire primary key?
What is the condition for a table to be in Boyce-Codd Normal Form (BCNF)?
What is the condition for a table to be in Boyce-Codd Normal Form (BCNF)?
What is the purpose of dividing large tables into smaller tables in normalization?
What is the purpose of dividing large tables into smaller tables in normalization?
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Which normal form ensures that each table cell must contain a single value?
Which normal form ensures that each table cell must contain a single value?
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What is the condition for a table to be in Domain-Key Normal Form (DKNF)?
What is the condition for a table to be in Domain-Key Normal Form (DKNF)?
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What is the main advantage of eliminating data redundancy in a database?
What is the main advantage of eliminating data redundancy in a database?
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A table is in 2NF, but a non-key attribute depends on another non-key attribute. What should be done to bring the table to 3NF?
A table is in 2NF, but a non-key attribute depends on another non-key attribute. What should be done to bring the table to 3NF?
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What is the purpose of vertical partitioning in normalization?
What is the purpose of vertical partitioning in normalization?
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Why is denormalization used in some databases?
Why is denormalization used in some databases?
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What is the rule of normalization that states each row in a table should have a unique combination of values?
What is the rule of normalization that states each row in a table should have a unique combination of values?
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What is the result of eliminating transitive dependencies in a database?
What is the result of eliminating transitive dependencies in a database?
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Study Notes
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.
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Description
Learn about the process of organizing database fields and tables to minimize data redundancy and dependency. Discover the different normal forms and how they work.
