1. Introduction to Database System Prof. Dr. Amany Sarhan 2017.................. Computer and Control Engineering Faculty of Engineering Tanta University

2. Agenda What is the data base? Properties of Database Database models Database system and its components DBMS

3. A typical domestic ‘ database ’ Is this Organised? Efficient? Easily accessible? Flexible? …… good for much other than keeping things off the floor?

4. Paper based databases Have been around for a long time Data is organised and quickly accessible So is easier to maintain – fewer errors But is not all that flexible – things are filed in one place only (why would it not be a good idea to have duplicates)

5. Paper based databases Can it be searched easily? Can we insert data between organized data?? Can we make a quick report ? Can this report be rewritten easily if we add new data??

6. Why Study Databases?? Datasets increasing in diversity and volume. Digital libraries. Interactive video. Human Genome project. Moreover, it is fun to study!!

7. Why study database?? Databases are useful Many computing applications deal with large amounts of information Database systems give a set of tools for storing, searching and managing this information

8. What is a Database? “A set of information held in a computer” Oxford English Dictionary “One or more large structured sets of persistent data, usually associated with software to update and query the data” Free On-Line Dictionary of Computing “A collection of data arranged for ease and speed of search and retrieval” Dictionary.com

9. What is a Database? A database is any collection of facts that are systematically organized Collection of related data A self-describing collection of data element, together with relationships among those elements A collection of data items that are treated as a unit An example of a database is the library card Each card, contains facts (author, title, call number) that are organized (alphabetically by title) to make finding the item much easier

10. Examples of Databases Library catalogues Medical records Bank accounts Stock control Personnel systems Product catalogues Telephone directories Train timetables Airline bookings Credit card details Student records Customer histories Stock market prices Discussion boards and so on…

11. Database Users End users Use the database system to achieve some goal Application developers Write software to allow end users to interface with the database system Database Administrator (DBA) Designs & manages the database system Database systems programmer Writes the database software itself

12. Database properties A database represents some aspect of the real world. A database is a logically coherent collection of data with some inherent meaning. A database is designed, built, and populated with data for a specific purpose. A database can be of any size and of varying complexity A database may be generated and maintained manually or by machine.

13. What is a Database? Database is a structured object. That structured object consists of data and metadata, Data in a database is the actual stored descriptive information. Metadata describes the structure applied by the database to the customer data.

14. Data and meta data AreaCorresponding Data Needed UniversityStudents, Staff, Facilities, Building……… CompaniesProduct, Employee, Customers, Accounts HospitalPatient, Employee, Doctors, Pharmacy…….. LibraryBook, Publisher…….. LabMachine, Maintains Co. BankCustomers, Employee ……. …….. Attribut (field) Name TypeComment Patient_Id # NumberPrimary Key Name Character Age Number City Character Phone_number Number diagnosis Characterbetween(Ca, Ked,Heart) ……..

15. What Is a Database System? A database system is essentially computerized record-keeping system. The database itself can be regarded as a kind of electronic filing cabinet; Variety of operations on such files, Database systems allow users to StoreUpdate Retrieve Organise Protect their data.

16. Database systems components Data Data User User Application Application HW HW SW SW

17. Hardware components of DBS secondary storage The secondary storage volumes—that are used to hold the stored data, together with the associated I/O devices, device controllers, I/O channels, and so forth. processor(s) The hardware processor(s) and associated main memory that are used to support the execution of the database system software

18. Database Definition Creation Revision Integrity Controls Retrieval (Query/Reports) Update (Transaction Processing) DBMS Database Control System User Environment Input Data Transactions Data Retrieval Requests Output System Data: Database Definition User Schemas Transaction Defns Query/Report Defns  DATABASE User Application Processes A Database Application System DBMS

19. What is an Application? An application is a piece of software that runs on a computer and performs a task. That task can be interactive and use a graphical user interface (GUI), and can execute reports requiring the click of a button and subsequent retrieval from a printer.

20. Data Data; Refer to the values actually stored in the database. Users A single-user system is a system in which at most one user can access the database at any given time. A multi-user system is a system in which many users can access the database at the same time. In general, then, the data in the database will be both integrated and shared,

21. Database Management Systems (DBMS) A database is a collection of information A database management system (DBMS) is the software than controls that information Examples: Oracle DB2 (IBM) MS SQL Server MS Access Ingres PostgreSQL MySQL

22. DBMS DBMS The required SW is the DBMS which is: DB manager DB server or DB Engine) A layer of software between the physical database itself and the users of the system, ( DB manager or DB server or DB Engine). All requests of users to access to the database are handled by the DBMS. General function provided by the DBMS is shielding of database users from hardware-level details. It provides controllable access over the database.

23. What the DBMS does??? DBMS provides Persistence Concurrency Integrity Security Data independence Data Dictionary Describes the database itself

24. Objectives of DBMS MANAGEMENT of Data Resources AVAILABILITYINTEGRITY SHARABILITY EVOLVABILITY “Future Availability” Across: Users Functions Orgn Units Changing: Needs Technology Existence Quality Privacy of Data. Online Interactive Fast response High-level tools Logical View of Data usecontrol N DBMS