Chapter 8 Flashcards
Relational database
a database where
the data items are linked by internal
pointers.
Table
a group of similar data, in a
database, with rows for each instance of
an entity and columns for each attribute.
Record (database)
a row in a table in a
database.
Field
a column in a table in a database.
Tuple
one instance of an entity, which
is represented by a row in a table.
Entity
anything that can have data
stored about it, for example, a person,
place, event, thing.
Attribute (database)
an individual data
item stored for an entity, for example, for
a person, attributes could include name,
address, date of birth.
Candidate key
an attribute or smallest
set of attributes in a table where no tuple
has the same value.
Primary key
a unique identifier for a
table. It is a special case of a candidate
key.
Secondary key
a candidate key that is
an alternative to the primary key.
Foreign key
a set of attributes in one
table that refer to the primary key in
another table.
Relationship
situation in which one
table in a database has a foreign key that
refers to a primary key in another table
in the database.
Normalisation (database)
the process of organising data to be stored in a database into two or more tables and relationships between the tables, so that data redundancy is minimised.
First normal form (1NF)
the status of
a relational database in which entities
do not contain repeated groups of
attributes.
Second normal form (2NF)
the status of a relational database in which entities are in 1NF and any non-key attributes depend upon the primary key.
Third normal form (3NF)
the status of
a relational database in which entities
are in 2NF and all non-key attributes are
independent.
Composite key
a set of attributes that
form a primary key to provide a unique
identifier for a table.
Database management system
DBMS
systems software for the
definition, creation and manipulation of
a database.
Data management
the organisation
and maintenance of data in a database to
provide the information required.
Data dictionary
a set of data that
contains metadata (data about other
data) for a database.
Data modelling
the analysis and
definition of the data structures required
in a database and to produce a data
model.
Logical schema
a data model for a
specific database that is independent of
the DBMS used to build that database.
Access rights (database)
the
permissions given to database users to
access, modify or delete data.
Developer interface
feature of a
DBMS that provides developers with
the commands required for definition,
