Databases & Database Users Chapter 1 Text book sections: All December 31, 2022 ICS324 1 Outline Introduction Steps in DB design Characteristics of the Database Approach Advantages of Using the DBMS Approach When Not to Use a DBMS Actors on the Scene Workers behind the Scene Types of Database Systems Summary December 31, 2022 ICS324 2 Introduction Database Collection of related data Known facts that can be recorded and that have implicit meaning Miniworld or universe of discourse (UoD) Represents some aspect of the real world Logically coherent collection of data with inherent meaning Built for a specific purpose December 31, 2022 ICS324 3 Traditional File Approach Vs DB approach Traditional file approach Application DB DB approach Application December 31, 2022 DBMS ICS324 DB 4 Three Tier Architecture December 31, 2022 ICS324 5 Example: Requirements of a COMPANY The company wants a record of each employee’s name, id, age, …. An employee can have many dependents An employee can work in many projects Each project has a name, a unique number, a location …. An employee belongs to one department A project belongs to one department A department has a unique number, a manager, and many locations …. …. ... December 31, 2022 ICS324 6 December 31, 2022 ICS324 7 FIGURE 7.2 Result of mapping the COMPANY ER schema into a relational schema. December 31, 2022 ICS324 8 CREATE TABLE – Example 1 December 31, 2022 ICS324 10 Introduction (cont'd.) December 31, 2022 ICS324 11 Introduction (cont'd.) Database management system (DBMS) Collection of programs Enables users to create and maintain a database Meta-data Database definition or descriptive information Stored by the DBMS in the form of a database catalog or dictionary Application program : Accesses database by sending queries to DBMS December 31, 2022 ICS324 12 Introduction (cont'd.) Defining a database : Specify the data types, structures, and constraints of the data to be stored Manipulating a database Query and update the database miniworld Generate reports Transaction : May cause some data to be read and some data to be written into the database Protection: Includes internal and external protection Maintain the database system : Allow the system to evolve as requirements change over time December 31, 2022 ICS324 13 Characteristics of the Database Approach Traditional file processing: Each user defines and implements the files needed for a specific software application Database approach: Single repository maintains data that is defined once and then accessed by various users Main characteristics of database approach Self-describing nature of a database system (using the sys catalog meta-data instead of describing data in the application) Insulation between programs and data, and data abstraction Support of multiple views (a scope to display certain sub tables of the data) of the data Sharing of data and multiuser transaction processing December 31, 2022 ICS324 14 Advantages of Using the DBMS Approach Controlling redundancy Restricting unauthorized access Providing persistent storage for program objects Providing storage structures and search techniques for efficient query processing Providing backup and recovery Providing multiple user interfaces Representing complex relationships among data Enforcing integrity constraints Permitting inferencing and actions using rules (eg. Triggers) December 31, 2022 ICS324 15 Advantages of Using the DBMS Approach (cont'd.) Additional implications of using the database approach Reduced application development time Flexibility Availability of up-to-date information (a single repo) Economies of scale December 31, 2022 ICS324 16 When Not to Use a DBMS No need to use a DBMS for: Simple, well-defined database applications not expected to change at all Stringent, real-time requirements that may not be met because of DBMS overhead Embedded systems with limited storage capacity No multiple-user access to data December 31, 2022 ICS324 17 Actors on the Scene Database administrators (DBA) are responsible for: Authorizing access to the database Coordinating and monitoring its use Acquiring software and hardware resources Database designers are responsible for: Identifying the data to be stored Choosing appropriate structures to represent and store this data End users System analysts: Determine requirements of end users Application programmers : Implement these specifications as programs December 31, 2022 ICS324 18 Actors on the Scene December 31, 2022 ICS324 19 Workers behind the Scene DBMS system designers and implementers: Design and implement the DBMS modules and interfaces as a software package Tool developers: Design and implement tools Operators and maintenance personnel: Responsible for running and maintenance of hardware and software environment for database system December 31, 2022 ICS324 20 BDA Tools December 31, 2022 ICS324 21 Types of Database Systems Traditional databases: Store textual or numeric information Multimedia databases: Store images, audio clips, and video streams digitally Geographic information systems (GIS) : Store and analyze maps, weather data, and satellite images Data warehouses and online analytical processing (OLAP) systems Extract and analyze useful business information from very large databases Support decision making Real-time and active databases December 31, 2022 Control industrial and manufacturing processes ICS324 22 Summary Database : Collection of related data (recorded facts) DBMS : Generalized software package for implementing and maintaining a computerized database When not to use a DBMS Several categories of database users Advantages of using a DBMS approach December 31, 2022 ICS324 23 Disclaimer Parts of the lecture slides contain original work from the authors of your text book December 31, 2022 ICS324 24 25
