A-level Computing/AQA/Problem Solving, Programming, Operating Systems, Databases and Networking/Databases

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From the Specification : Database
  • Conceptual data model
  • Entity Relationship modelling

Produce a data model from the given data requirements for a simple scenario involving two or three entities.

  • Database Design and Normalisation techniques

Be able to normalise relations to Third Normal Form.

From the Specification : Relational Databases

Explain the concept of a relational database.

Define the terms:

  • attribute,
  • primary key,
  • composite key,
  • foreign key,
  • referential integrity.
From the Specification : Querying a Database

Learn about Structured Query Language (SQL)

Use SQL to retrieve, update, insert and delete data from several tables of a relational database (see Teacher Resource Bank)

Data Definition Language (DDL)

Explain the term DDL. Use DDL to define a database (see Teacher Resource Bank for commands/statements).

Conceptual Data Model[edit]

http://en.wikipedia.org/wiki/Conceptual_schema

Entity Relationship Diagrams[edit]

An entity relationship diagram is used at the Analysis stage to help the analyst to model and represent the entities involved in the problem domain. These models can then be developed into designs for tables and relationships in a proposed database system.



Relationships[edit]

entity relationship

Referential integrity[edit]

Referential_integrity

Foreign Key[edit]

Tuple sometimes called a record, a set of attribute values, (a row of a table)

Attribute a named column in a table

Primary Key a attribute that uniquely identifies a tuple

Relation a table

Relational Database a collection of tables

Composite Key where a collection of attributes uniquely identify a tuple rather than just one

Foreign Key An attribute in one table that is a Primary key in another table, often there to reference to said table later

Database Design and Normalisation[edit]

Database Design[edit]

Relational Databases[edit]