Relational Model Flashcards
Simply a sequence (or list) of values
Tuple
refer to a column of a table
attribute
the logical design of the database
database schema
if elements of the domain are considered to be indivisible unit
Atomic Domain
consists of a collection of table
Relational Database
Special value that signifies that the value is unknown or does not exist
Null Value
a set of one or more attributes that, taken collectively, allow us to identify uniquely a tuple in the relation
Superkey
used to refer to a row
table
a language in which a user requests information from the database.
Query Language
A visual representation of the database system’s structure and organization
Schema Diagram
the user instructs the system to perform a specific sequence of operations on the database to compute the desired result.
Imperative query language
used to refer a table
relation
a table represent relationship among a set of value
Row
a set of permitted values
Domain
an attribute (or collection of attribute) in a relation, that refers to the primary key in another relation.
Foreign Key
a candidate key that is chosen by the database designer
Primary Key
corresponds to the programming language notion of type definition
Relation Schema
refers to a specific instance of relation, that is, containing specific set of row
Relation Instance
are superkeys which no proper subset
Candidate Key
a snapshot of the data in the database
Database Instance
