Databases - OCR Computer Science A Level

These flashcards cover key concepts and terminology related to databases, specifically focusing on relational databases, SQL, and normalization principles.

Relational Database

A database that creates different tables for each entity to recognize their differences.

Entity

An item of interest about which information is stored in a database.

Primary Key

A unique identifier for each record in a table.

Foreign Key

An attribute that links two tables together, existing as a primary key in one and a foreign key in another.

Secondary Key

Allows a database to be searched quickly, improving data retrieval.

Normalisation

The process of organizing data to reduce redundancy and improve data integrity.

First Normal Form (1NF)

A state where no attribute contains more than a single value.

Second Normal Form (2NF)

A database in first normal form without any partial dependencies.

Third Normal Form (3NF)

A database in second normal form with no non-key dependencies.

Indexing

A method to store the position of each record ordered by a certain attribute.

SQL

Structured Query Language used to manipulate databases.

Referential Integrity

Ensures that relevant information is not removed if it is required elsewhere.

Transaction Processing

The execution of a single operation on data that can include multiple operations.

ACID

A set of properties (Atomicity, Consistency, Isolation, Durability) to ensure reliable database transactions.

Record Locking

The process of preventing simultaneous access to records to avoid inconsistencies.

Redundancy

Having one or more copies of the data to prevent loss.

Entity Relationship Modelling

A diagrammatic representation of entities and their relationships in a database.

JOIN

Combines rows from multiple tables based on a common field.

CREATE TABLE

SQL command used to create a new database table with specified attributes.

ALTER

SQL command used to add, delete, or modify columns in a table.

DELETE

SQL command used to remove records from a database table.

INSERT INTO

SQL command used to add a new record into a database table.

UPDATE

SQL command used to modify existing records in a database table.