Databases - CS Fundamentals

Databases - CS Fundamentals

• Flat-file databases: Simplest database type. Store data in a single table (a flat file). Data organization is inflexible, making querying and updating challenging. Managing relationships between different pieces of information is difficult.

• Entity Relationship Diagrams (ERDs): Visual models representing entities (objects) and relationships in a database. Used to design database structure before implementation. Show entities as rectangles, attributes as ellipses, and relationships as diamonds. Essential for database design.

• Relational Database: Organize data in multiple interconnected tables. These tables have predefined relationships linking related data. Offers a structured approach for complex datasets, unlike flat files' limitations. Improves query capabilities, data integrity, and maintenance.

• Flat File: A simple text file of data organized as rows and columns. Lacks a defined structure or relationships to other tables. Often used for small datasets or situations not needing complex structuring.

• Primary Key: A unique identifier for each record in a table, ensuring each row is distinct. Critical for data integrity and record retrieval. Ex: Student ID in a student database.

• Foreign Key: A field in one table referencing another table's primary key. Links tables and enforces referential integrity. Maintains data relationships.

• Secondary Key: A non-unique key enabling retrieval of multiple records. Less critical to relational database integrity than primary and foreign keys, but speeds querying.

• Entity Relationship Modelling: Designing a relational database by identifying entities, attributes, and relationships. Essential for converting data requirements into functional structures meeting user specifications.

• Normalization: Reduces data redundancy and enhances data integrity in relational databases. Involves dividing large tables into smaller tables and defining relationships. Aims for a more efficient and structured database.

• Indexing: Data structures improving data retrieval speed, acting like an index for a book. Significantly speeds up data searches and queries within the database.