CHAPTER 1 What is Data?

Database

A collection of related data

Database Management System (DBMS)

A software package/system to facilitate the creation, and maintenance of a computerized database.

Casual

Access database occasionally when needed.

Queries

Access different parts of data and formulate the result of a request

Program data independence

Allows changing data structures and storage organizations without having to change the DBMS access programs.

Actors on the scene

Database Administrators, Database Designers, End-users

Database Designers

Define the content, structure of the database

Sophisticated

Includes business analysts, scientists, engineers

Data

Known facts that can be recorded, and have an implicit meaning

Transactions

Read some data, "update" certain values/generate new data, and store that the database

Standard

Refers to data item names, display formats, screens, report structures, metadata (description of data), Web page layouts, etc.

Database Administrators

The "power-force" of the database. Controlling, monitoring, and coordinating the database itself.

Database System

The DBMS software together with the data itself. Sometimes, the applications are also included.

Meta-data

The description that is stored by a DBMS catalog in a particular database (e.g. data structures, types, constraints)

Naive

They make up a large section of the database accessors.

End-users

They use the data for queries, reports, and some of them update the database content. Can be categorized to 4 types: Casual, Naive, Sophisticated, and Stand-alone.

Data model

Used to hide storage details and present the users with a conceptual view of the database

[Typical DBMS Function] Define...

... a particular database in terms of its data types, structures, and constraints

[Typical DBMS Function] Processing and Sharing...

... by a set of concurrent users and application programs - yet keeping all data valid and consistent

[Typical DBMS Function] Construct...

... the initial database contents on a secondary storage medium

Stand-alone

Maintains personal databases using ready-to-use packaged applications.

Mini-world

Some part of the real world about which data is stored in a database

[Typical DBMS Function] Manipulating the database (3 things):

(1) Retrieval: Querying, generating reports (2) Modification: Insertion, deletion, and updates to its content (3) Accessing the database through Web applications