Normalization_database_EERD_education,presentation.pptx

normalization, database

1. Welcome to My PowerPoint Presentation on; Normalization In Relation to DBMS

2. Introduction B .I.T / FUNDAMENTALS OF DATABASE MANAGEMENT SYSTEMS

3. Introduction to Normalization in Database. Normalization is a technique for a set of relations with desirable properties ,given the data requirements of an enterprise. Purpose/Objectives/Importance Minimize Redundancy or data duplication. Ensure data dependencies or maintain data accuracy and integrity. Improve database efficiency and flexibility. Improve Query Performance The Process of Normalization Identify entities and relationships Organize data into tables. Apply normal forms.

4. Introduction to Normalization in Database. Normalization is a technique of organizing the data in to multiple related tables to minimize data redundancy. Issues due to data redundancy. Insertion Anomaly Deletion Anomaly Updating Anomaly Normalization divides and holds data in to separate , logical , independent entities and relates them using a commo

5. First Normal Form (1NF) Unnormalized Form(UNF)— A table that contains one or more repeating groups. First Normal Form (1NF)--- A relation in which the intersection of each row and column contains one and only one value. A table is in 1NF if it contains only atomic values and each entry in a column is of the same data type. Rules: Each table cell/column should contain a single value Each record should be unique(unique name) Each value stored in each respective column should be of the same type. The order in which the data is saved doesn’t matter.

6. Second Normal Form(2NF) Second Normal Form(2NF) – A relation that is in first normal form and every non primary key attribute is fully functionally dependent on the primary key. -2NF applies to relations with composite keys(a primary key composed of 2 or more attributes) Note : A key refers to the attributes that uniquely identify each row. -A table is in 2NF if it is in 1NF and all non-key attributes are fully functionally dependent on the entire primary key. Rules: No partial dependency on any subset of the composite primary key.

7. Third Normal Form(3NF) Third Normal Form(3NF)– A relation that is in first and second normal form and in which no non-primary-key attribute is transitively dependent on the primary key. -A table is in 3NF if it is in 2NF and all attributes are only dependent on the primary key, with no transitive dependencies. Rules: Remove transitive dependency(non-key attribute depending on another non-key attribute)

8. Denormalization Denormalization: - I the process of combining tables to improve read performance by reducing the need for joins. Purpose: -Used when read performance is a higher priority than maintain strict data integrity. Merits of denormalization Demerits of denormalization Can improve performance by; Precomputing derived data Minimizing the need for joins Reducing the number of foreign keys in relations Reducing the number of indexes(thereby saving storage space) Reducing the number of relations May speed up retrievals but can slow down updates. Always application-specific and needs to be re-evaluated if the application changes. Can increase the size of relations. May simplify implementation in some cases but may make it more complex in others. Sacrifices flexibility.

9. Thanks for Listening Presented by; Ssemaganda Charles Harry