Chapter 3 Flashcards
(15 cards)
Bridge Relation
The relation that represents an M:N relationship.
Column
relation in a table
Field
A placeholder where Word inserts content in a document. Word automatically uses fields when specific commands are activated, such as those for inserting dates, page numbers, and a table of contents.
Foreign Key
Column in a relation that refers to a primary key column in another (referred) relation
- A mechanism that is used to depict relationships in the relational database model
- For every occurrence of a foreign key, the relational schema contains a line pointing from the foreign key to the corresponding primary key
Primary Key
Column (or a set of columns) whose value is unique of each row
- Each relation must have primary key
- The name of the primary key column is underlined in order to distinguish it from the other columns in the relation
Record
a collection of related data elements
Relation
table in a relational database
- Two additional properties of each table:
- Order of columns is irrelevant
- Order of rows irrelevant
Relational Database
Rules that a relational
Relational Database Model
Logical Database model that represents a database as a collection of related tables
Relational DBMS
Most contemporary commercial DBMS software packages, are (RDBMS) software packages
Relational Schema
Visual depiction of the relational database model
Relational Table
A set of data elements (values) that is organized using a model of vertical columns (which are identified by their name) and horizontal rows, the cell being the unit where a row and column intersect.
Row
a horizontal group of cells in a worksheet identified by numbers
Table
An arrangement of data made up of horizontal rows and vertical columns.
Tuple
a row in a table that contains data about a specific item in a database table
