BLM 258 Chapter 1 Databases and Database Users

BLM 258 Chapter 1: Databases and Database Users 1 Fundamentals of Database Systems Elmasri-Navathe

2 Introduction Basic Operations on Databases Example University Database Characteristics of the Database Approach Database Users Advantages of Using the Database Approach

3 Introduction Traditional Database Applications: Used for textual or numeric information. Multimedia Databases: Used for images and video streams. GIS: Maps, weather data and satellite images. OLAP Systems: Useful information from very large databases. Active Databases: Control real-time manufacturing processes

4 Introduction Database: Basically it is defined as collection of related data. Databases represents a small part of real world called miniworld. Databases record known facts with implicit meaning and they are created for a specific purpose.

5 Introduction Database Management System (DBMS) is defined basically as a collection of programs. DBMS is used to create and maintain a database. Examples of popular databases: Amazon. com Youtube. com Meta-data It is an important concept: is not the actual data stored in database. It defines the database structure.

6 Basic Database Operations Defining a database: Specification of data types, structures and constraints on data. (meta-data) Manipulating Querying a database: and updating the database The actual purpose of creating databases and the main part of this course is about this functionaltiy.

7 Basic Database Operations Sharing a database: Many users and application programs can access database simultaneously (airline reservation systems-many agents may be able book seats) Maintaining Adjusting a database: database to the requirements changed over time.

8 Example University Database Defining Data University Database about each student, course, section, grade report and prerequisites The main database that will be used in this course Relationships amonf the different records Manipulating database: Involves querying and updating

9 Example University Database Examples Produce of queries: the grade report of a specific student Provide the names of students who took Data Structures course in 2007 Fall semester. List the prerequisities of the Intro to Computer Science course List the instructors of each section for Database course

10 Example University Database Examples Define of updates: a new section for the Data Structures course Update the class of a specific student to sophomore Enter a grade of ‘A’ for a specific student in Discrete Math. course

11 Example University Database Phases for designing a database: Requirements specification and analysis Conceptual design Logical design Physical design

12 Characteristics of the Database Approach Self-describing nature of a database: Using meta-database system defines complete structure and constraints. Meta-data is used by DBMS software to handle all operations and it is also used by users who want to learn about database structure. Insulation between programs and data: Program-data independence Program-operation independence

13 Characteristics of the Database Approach Support of multiple views of the data: Each user’s view can be different. Actually it is necessary, different users may need different facilities. Sharing of data and multiuser transaction processing: Multiple users can access database at the same time. Concurrency control software is used to allow users to update database at the same time in a controlled manner.

14 Characteristics of the Database Approach Transaction: It is defined as an executing program or process that operates on databases. Each transaction need to have the following proporties: Isolation: Each transaction need to execute in isolation from other transactions. Atomicity: All the operations in a transaction need to be executed or none are.

15 Database Users Actors on the Scene Database Administrators (DBA) Database Designers End Users Casual end users Parametric end users Sophisticated end users Standalone users System Analysts Application Programmers

16 Database Users Workers behind the Scene DBMS system designers and implementers Tool developers Operators Maintenance Personnel

17 Advantages of Using the DBMS Approach Controlling redundancy is one of the important advantages. Using databases instead of files actually eliminate redundant information Data normalization Eliminating Database unauthorized access security Privileged software

18 Advantages of Using the DBMS Approach Databases provide persistent storage for program objects Complex oblects defined in any programming language can be stored permanently in database. This types of systems can be called as objectoriented DBMS. They also provide search techniques and storage methods to handle query processing efficiently. Indexes Caching Query optimization

19 Advantages of Using the DBMS Approach Databases provide backup and recovery Databases provide multiple user interfaces especially graphical user interfaces (GUIs) Databases represent complex relationships among data They enforce integrity constraints They allows inferencing using rules

20 Advantages of Using the DBMS Approach Reduced application development time Flexibility Availability of up-to-date information Scaling