Databases
A collection of related data
Database
This is a basic concept for the ER model and specific things or objects in the mini-world.
Entity
A minimal superkey.
Key
For each regular (strong) entity type in the ER schema, create this.
Relation
This is used to select a subset of the tuples from a relation based on a condition.
Selection
Description of a database including database structure, data types, and the constraints on the database.
(Database) Schema
This type of attribute has multiple values to describe entity.
Multi-valued attribute
This is an ordered set of values.
Tuple
For each regular 1:N relationship type, create this.
Foreign key
This is a condition for group by.
Having
A software package/ system to facilitate the creation and maintenance of a computerized database.
DBMS
A relationship type between the same participating entity type in distinct roles.
Recursive Relationship (self-referencing)
This is used to represent values that are unknown or not available or inapplicable in certain tuples.
Null
For each multivalued attribute, create this.
Relation
The sequence of cartesian product followed by select.
Join
This stores the description of a particular database (e.g. data structures, types, and constraints).
Catalog (Meta-data)
This is value sets of attributes in ER model.
Domain
Relational model was first proposed by this at IBM Research.
Dr. E.F. Codd
How many different options to map Super/Subclasses.
4
The two operand relations R and S in Union operation must be this.
Type (Union) compatible
This is proposed to support DBMS characteristics of, i.e, Program-data independence and Support of multiple views of the data.
Three-Schema Architecture
This has a constraint that every subclass has only one superclass.
Hierarchy
A constraint involving two relations.
Referential Integrity
For mapping a category whose defining superclass have different keys, specify a new key attribute, called this.
Surrogate key
This operation is used to combine tuples from two relations in a combinatorial fashion.
Cartesian (cross) Product