8 Databases Flashcards
Database
A structured collection of items that can be addressed by different applications programmes
Relational database
A database where the data base items are inclined by internal data pointers
Table
A group of similar data , in a database, with rows from each instance of an entity and columns for each attribute
Record
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 e.g and event, thing, person
Attribute
An individual item stored for an entity, for example a person could include attributes like name, date of brith
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 refers 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
Referential integrity
Property of a database that does not contain any values of a foreign key that are not matched to the corresponding primary key
Index
A data structure built from one or more columns in a database table to speed up searching for data