Detailed Notes on Databases in A-Level Computer Science Curriculum (copy)

Database

A structured collection of data organized around a specific topic, allowing for persistent storage.

DBMS (Database Management System)

Specialized software that allows users to create, manage, and manipulate databases effectively.

Tables

Primary components of databases, consisting of records (rows) and fields (columns) that define characteristics of entries.

Primary Key

A unique identifier assigned to each record in a table to ensure data integrity.

Foreign Key

A field in one table that references the primary key of another table to establish relationships between them.

Referential Integrity

A rule that ensures relationships between foreign keys and primary keys are maintained correctly within a database.

Indexes

Specialized data structures that enhance the speed and efficiency of data retrieval operations.

Data Normalization

The process of organizing data into separate tables to reduce redundancy and dependency.

1NF (First Normal Form)

Eliminates duplicate columns in a table and ensures all fields contain atomic values.

2NF (Second Normal Form)

Requires compliance with 1NF and mandates all data in a table must fully depend on the primary key.

3NF (Third Normal Form)

Ensures there are no transitive dependencies among non-key attributes in a dataset.

Entity Relationship Diagram (ERD)

A visual representation illustrating how different entities or tables within a database relate to one another.

SELECT command

Retrieves data from one or more tables, allowing specification of desired columns.

JOIN Operations

Combine rows from two or more tables based on related columns to retrieve data.

Data Dictionary

A system catalog that manages metadata about the database structure.

Query Processor

Interprets SQL queries and returns results, optimizing query performance.

Data Safety

Features ensuring proper backup and recovery protocols to maintain data integrity.

User Access Control

Mechanisms for permission settings managing who can view or manipulate the database.