CHAPTER 1 What is Data?

[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

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

Stand-alone

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

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.

Mini-world

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

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] 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