Db lec 04_new
- 1. + Dr Ramadan Babers Faculty of Science - Helwan University Fall 2018 D B LEC-04
- 2. Entity-Relationship Model (ER Model) 2 Degree of Relationship Many-to-many: One entity from A can be associated with more than one entity from B and vice versa.
- 8. Entity-Relationship Model (ER Model) 8 Degree of Relationship How to Handle a Many-to-Many Relationship in Database Design
- 9. + Database Systems Basic Concepts 9
- 10. 1- Areas of Database Study 10 DBMS software Database Design Query Languages Application Programming Database Administration Data Warehousing & Data Mining
- 11. 2- Characteristics of the Database Approach 11 insulation of programs & data support of multiple user views use of a catalog to support database descriptions DB A collection of described and interrelated data storedand managed by general purpose DBMS
- 12. 3- DBMS Functions 12 Data Dictionary Data Storage Management Data Transformation and Presentation Security Multi-user Access Control Backup and Recovery Data Integrity Database Access Language Database Communication Interface
- 13. 4- Database System Environment 13 DBMS Software Application Programs/Queries Software: Query Processing & programs Software: DataAccess Database System Users/Programmers Database Definition Database
- 14. 5- Database Approach 14 Data definition language (DDL). Permits specification of data types, structures and any data constraints. All specifications are stored in the database. Data manipulation language (DML). General enquiry facility (query language) of the data.
- 15. 6- Components of DBMS Environment 15
- 16. 6- Components of DBMS Environment (cont.) 16 Hardware Can range from a PC to a network of computers. Software DBMS, operating system, network software (if necessary) and also the application programs. Data Used by the organization and a description of this data called the schema.
- 17. 6- Components of DBMS Environment (cont.) 17 Procedures Instructions and rules that should be applied to the design and use of the database and DBMS. People
- 18. 7- Database Players (3 types) 18 DBA access authorization, coordination & monitoring database usage, problem determination, performance tuning etc Designers identify the requirements & chose the appropriate structures to represent & store the data Users (Casual, parametric, Sophisticated, stand-alone) System analysts & application programmers DBMS system designers & implementers Tool developers Operators & maintenance personnel
- 19. 8- Database User Types (4 types) 19 Users (Casual, parametric, Sophisticated, stand-alone) Casual end users occasionally access the database, but they may need different information each time.They use a sophisticated database query language to specify their requests and are typically middle- or high-level managers or other occasional browsers. Naive or parametric end users make up a sizable portion of database end users.Their main job function revolves around constantly querying and updating the database, using standard types of queries and updates—called canned transactions.
- 20. 8- Database User Types (cont.) 20 Sophisticated end users include engineers, scientists, business analysts, and others who thoroughly familiarize themselves with the facilities of the DBMS in order to implement their own applications to meet their complex requirements. Standalone users maintain personal databases by using ready-made program packages that provide easy-to-use menu- based or graphics-based interfaces. An example is the user of a tax package that stores a variety of personal financial data for tax purposes.
- 21. 9- DBMS Interfaces 21 Menu-based Interfaces for browsing Forms-based Interfaces GUIs Natural Language Interfaces Specialized Interfaces Interfaces for the DBA Query Language