Normalization
Download as PPTX, PDF
2 likes370 views
The document discusses database normalization. Normalization is the process of minimizing data redundancy in tables. It defines different types of dependencies like functional dependency, partial dependency, and transitive dependency. The document also describes different normal forms like 1NF, 2NF, 3NF, and 4NF that tables must conform to during normalization to minimize anomalies like insertion, modification, and deletion anomalies.
Normalization
- 1. Muhammad Umair Oracle Database 11g Developer Track
- 2. Normalization A process of minimizing data redundancy/duplication from relation/tables
- 3. Simple Dependency/ Functional Dependency All attribute are depends on Primary key Partial Dependency Some attribute are dependent on part of primary key Transitive Dependency Dependency of an attribute on Primary key through another attribute Multi-valued Dependency If two or more multi-valued attributes are merged in one relation then that relation will be hold multi-valued dependency
- 4. Normalization A process of minimizing data redundancy/duplication from relation/tables Normalization is used for verification of tables/relations Anomalies The problem of un-normalized database can be Insertion anomalies Modification anomalies deletion anomalies
- 5. Normal Form In normalization process we have to check our relation/tables against some standards. Each of those standards are called a Normal Form First Normal Form : 1NF A table will be in 1NF if no repeating group/ Multi-valued attribute exists in it. Second Normal Form : 2NF A table will be in 2NF if it is already in 1NF and no partial dependency exists in it.
- 6. Third Normal Form : 3NF A table will be in 3NF if it is already in 2NF and no transitive dependency exists in it. Fourth Normal Form : 4NF A table will be in 4NF if it is already in 3NF and no multi-valued dependency exists in it.