Database memorization Terms

Database

is typically structured data which serves a related purpose and is easy to use.

Database Management System (DBMS)

provides a systematic interface to define, update, retrieve, and administer information in a database.

Database Administrator (DBA)

is a person who is responsible for managing and maintaining an

organization’s DBMS and databases

Structure Query Language (SQL)

Databases support the standard SQL language for interaction and store information in a structured relational format

NoSQL databases

lack a standard language for interaction and store information in a variety of non-relational formats depending on the specific DBMS.

A Legacy System

is an old, typically critical system that still works but is diHicult to maintain, adapt to new business needs, or integrate with modern systems

The Systems Development Life Cycle

is multiple phase development process that can be used to

accomplish a database design project.

NOTE: The phases are Planning, Requirements Gathering, Conceptual Design, Logical Design, Physical Design,

Construction, Implementation and Rollout, and Support

An Entity Type

describes a generic type of thing.

Entity

is a specific thing.

Attribute

is a characteristic that describes a thing.

Key

uniquely identifies an Entity.

A Relationship Type

describes a generic association between two Entities Types.

Relationship

is a specific association between two Entities.

Database Object Type

is a generic type of structure used within a DBMS to represent information within a database.

Database Object

is a specific instance of a structure used to represent information within a specific database.

Database Model

is a collection of database structure rules, such as Database Object Types, that may be used within a database.

A Entity-Relationship Diagram (ERD)

is a visual representation of a Data Model.

A Schema

is a specific Data Model implemented in a specific DBMS using a specific Database Model.

Conceptual Data Model

for a specific database’s design states what information is included at a high level. It is independent of a specific Database Model or DBMS.

A Logical Data Model

for a specific database’s design states what information is included as well as how that information is structured using a specific Database Model. It is independent of a specific DBMS.

A Physical Data Model

for a specific database’s design states what information is included, how that information is structured using a specific Database Model, as well as the implementation details using a specific DBMS.

Cardinality

defines the number of relationships that entities may participate in for specific relationship type.

A one-to-one (1-to-1) Cardinality

means that for each type of relationship, one entity of the first type can be related to at most one entity of the second type, and vice versa.

A one-to-many (1-to-N) Cardinality

means that for each type of relationship, one entity of the first type can be related to many entities of the second type, but each of entity of the second type can only relate back to that one entity of the first type.

A many-to-many (N-to-N) Cardinality

means for each type of relationship, one entity of the first type can be related to many entities of the second type, and vice versa.

A Strong Entity

does not have to be related to another entity in order for it to exist.

A Weak Entity

must be related to at least one other entity for it to exist.

An ID-Dependent Entity

is one whose unique identifier value (its Primary Key) includes the entire unique identifier value of another related Entity.