Database systems - 1.pptxdassdfsdf dasdas da

INtroduction to database system

1. Introduction to Database systems / Data Base management systems (3+1)

2. Books 1 . C . J. Date, "Database Systems", Addison Wesley, 2004, or Latest Edition. 2 . Cononolly and P. Begg, "Database Systems: A Practical Approach to Design, Implementation and Management", Addison Wesley, 2009, or Latest Edition. 3 . Elmasri and Navathe, "Fundamentals of Database Systems", Addison Wesley, 6th Edition, or Latest. 4 . Database Management Systems, 3rd Edition by Raghu Ramakrishnan , Johannes Gehrke . 5 . Fred McFadden, Jeffrey Hoofer, Mary Prescott, Modern Database Management , Prentice Hall, ISBN-10: 0132662256, 11th edition, 2012

3. Course Objectives 1 . Student should be able to demonstrate proficiency in database concepts Data modelling logical database design principles including ERD and Normalization. 2 . Student should be able to analyze database transaction, and its facilities like concurrency control, query optimization, backup and recovery and data warehousing and data mining. 3 . Student should be able to demonstrate its skills in SQL query writing and database administration

4. STORAGE & Files

5. Files A file, in the computer world, is a self-contained piece of information available to the operating system and any number of individual programs.

6. Basic file attributes Name – only information kept in human-readable form. Identifier – unique tag (number) identifies file within system. Type – needed for systems that support different types. Location – pointer to file location on device. Size – current file size. Protection – controls who can do reading, writing, executing. Time, date, and user identification – data for protection, security, and usage monitoring. Information about files are kept in the directory structure, which is maintained on the disk. Many variations, including extended file attributes such as file checksum. Information kept in the directory structure.

7. Attributes (Cont)

8. File Type Extensions

9. What if your operating system doesn't open the file. The most common illogical solution to make things correct is to RESTART the computer without knowing WHY? Reasons Why did this happen? How we can resolve this Issue Is file important for us?

10. What type of data or information file can store? Reasons Why we have to save the file? Where the information is saving? I am free to store all type Of information in file.

11. Using Word to store the data Let suppose A small Gym is using computer to store the members information (Membership and monthly payment). Team is not using any information system. Information is stored is on the basis of Word file on daily basis. What hurdles would occur if the team will continue using this?

12. Files Drawbacks A company has a large collection (say, 500 GB ) of data on employees, departments, products, sales, and so on. This data is accessed concurrently by several employees. Questions about the data must be answered quickly, changes made to the data by different users must be applied consistently, and access to certain parts of the data (e.g., salaries) must be restricted. We can try to manage the data by storing it in operating system files. This approach has many drawbacks, including the following: 1- We probably do not have 500 GB of main memory to hold all the data. We must therefore store data in a storage device such as a disk or tape and bring relevant parts into main memory for processing as needed. 2- Even if we have 500 GB of main memory, on computer systems with 32-bit addressing, we cannot refer directly to more than about 4 GB of data. We have to program some method of identifying all data items. 3- We have to write special programs to answer each question a user may want to ask about the data. These programs are likely to be complex because of the large volume of data to be searched. 4- We must protect the data from inconsistent changes made by different users accessing the data concurrently. If applications must address the details of such concurrent access , this adds greatly to their complexity. 5- We must ensure that data is restored to a consistent state if the system crashes while changes are being made. 6- Operating systems provide only a password mechanism for security . This is not sufficiently flexible to enforce security policies in which different users have permission to access different subsets of the data.