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Database Concepts and Entity Relationship Modelling

Database terminology: fields, records and keys

  • 3 things to know
  • A2 Unit 1

Overview

Primary key, composite key and foreign key.

What you need to know

Answer each one before you reveal it.

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Key term

What is a composite key?

Key term

What is a surrogate key, and why is one often used?

Key term

What is a view?

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    What is a field?

    Model answer

    A field is a single item of data held about something, such as a surname or a date of birth. A field is one column of a table and holds one kind of value.

  2. 2

    What is a record?

    Model answer

    A record is the complete set of fields held about one particular thing, such as one customer or one order. A record is one row of a table.

  3. 3

    What is a table?

    Model answer

    A table is a set of records that all hold the same fields, describing one kind of thing. A relational database stores all its data in tables.

  4. 4

    What is a primary key?

    Model answer

    A primary key is a field, or a combination of fields, whose value identifies each record in a table uniquely. A primary key may never be duplicated and may never be left empty.

  5. 5

    What is a composite key?

    Model answer

    A composite key is a primary key made up of two or more fields acting together, used where no single field is unique. A student number together with a course code identifies one enrolment.

  6. 6

    What is a foreign key?

    Model answer

    A foreign key is a field in one table whose values are the primary key of another table. A foreign key is how a relational database records a link between two tables.

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