Database Architecture

Flashcards based on database architecture lecture notes.

Hierarchical Model

A historical data model where every entity is subject to a higher one.

Hierarchical Model Drawback

One drawback is that data is stored in hierarchies physically.

Network Model

A database model that represents a more complex structure, allowing non-hierarchical structures.

Network Model Drawback

One drawback is that data is stored in linked sets physically.

Relational Model

A database model where data is stored in relations.

Relational Model

Is the relation the only construct in this model?

ANSI/SPARC

An organization that created a database model used as a general framework.

ANSI/SPARC Model Levels

How many levels does the ANSI/SPARC model consist of?

External Level

Users' views of the database - external schema.

Conceptual Level

Global definition/description of the database at the logical level - conceptual schema.

Internal Level

Global definition/description of the database at the physical level - internal schema.

Mapping

A process of transforming requests and results between the levels in the ANSI/SPARC model.

ANSI/SPARC Model Mapping

What mappings does the ANSI/SPARC Model have?

Data Independence

The capacity to change the schema at one level without changing the schema at the next higher level.

Logical Data Independence

Capacity to change the conceptual schema without changing any external schema.

Physical Data Independence

Capacity to change the internal schema without changing the conceptual schema.

Front-end

The end-user side of a system architecture.

Back-end

The database side of a system architecture.

Two Tier System Architecture

A system architecture with a client and a server.

Three Tier System Architecture

A system architecture with a client, application server, and database server.

Advantages of the 3 Tier Approach

What are the advantages of the 3 Tier Approach?

Web-enabled Database Architecture

Client application can be?

Data Definition Language (DDL)

Facilitates the creation and description of the database.

Data Manipulation Language (DML)

Facilitates the manipulation and processing of data.

Host Language

A programming language used with database systems.

Query Language

A language used to retrieve and manipulate data in a database.

SQL

SQL includes both DDL AND?

Database Systems

A practical approach to design, implementation and management of database systems

Introduction to Database Systems

An introduction to database systems

Web-enabled Database Architecture

Database systems based on 2-tier and 3-tier architectures are?