This document discusses the fundamentals of database systems. It outlines four key characteristics: the self-describing nature of databases through metadata stored in the DBMS catalog; insulation between programs and data through program-data independence; support of multiple views of data through user-specific subsets or views; and sharing of data and multiuser transaction processing through concurrency control in a multiuser environment.

1. FUNDAMENTALS OF DATABASE SYSTEMS
INTRODUCTION
Prepared By: GATZ

2. CHARACTERISTICS OF DBMS APPROACH
❖Self- describing nature of a Database System
❖Insulation between Programs and Data , and Data
abstraction
❖Support of Multiple Views of the Data
❖Sharing of the Data and multiuser transaction Processing

3. SELF-DESCRIBING NATURE OF A DATABASE SYSTEM
 Database System Database + Meta-data Stored in: DBMS Catalog
 Used by DBMS software and Database User
 DBMS software must work equally well with any number of any database
applications.
 In traditional file processing, data definition part of application
programs work with only one specific DB.

4. INSULATION BETWEEN PROGRAMS AND DATA, AND DATA
ABSTRACTION
 In traditional file processing – structure of data files is embedded in the
application programs.
 In database approach – structure of data files is stored in the DBMS catalog –
separate from access programs
(Program –data independence).

5. INSULATION BETWEEN PROGRAMS AND DATA, AND DATA
ABSTRACTION
 The characteristics that allows program-data independence is
called Data Abstraction.
 DBMS provides users with conceptual representation of
data.
 Data model – type of data abstraction – provides conceptual
representation.

6. SUPPORT OF MULTIPLE VIEWS OF DATA
 A database has many users , each of whom may require a different
view of database.
 A view – subset of database - contains virtual data derived from
database.

7. SHARING DATA AND MULTIUSER TRANSACTION PROCESSING
 A multiuser DBMS allows multiple users to access the database at the
same time.
 DBMS must include concurrency control.
 OLTP (Online Transaction Processing )- major part of database application.
 DBMS must enforce several transaction properties:
 I. Isolation II. Atomicity