Database management systems (DBMS) allow for the convenient and efficient storage and retrieval of interrelated data. A DBMS contains information about a particular enterprise through a collection of data and programs to access that data. It ensures the safety of stored information despite crashes or unauthorized access. Databases are used in many applications like banking, universities, sales, manufacturing and more to manage important information and perform tasks like registering students, assigning grades, and generating reports.
2. Database Management System (DBMS) A database-management system (DBMS) is a collection of interrelated data and a set of programs to access those data. The primary goal of a DBMS is to provide a way to store and retrieve database information that is both convenient and efficient. In addition, the database system must ensure the safety of the information stored, despite system crashes or attempts at unauthorized access.
3. DBMS DBMS contains information about a particular enterprise Collection of interrelated data Set of programs to access the data An environment that is both convenient and efficient to use
4. Database Applications Banking For customer information, accounts, and loans, and banking transactions. Airlines For reservations and schedule information. Universities For student information, course registrations, and grades. Credit & Transactions For purchases on credit cards and generation of monthly statements.
5. Cont.. Telecommunication For keeping records of calls made, generating monthly bills etc. Finance For storing information about holdings, sales, and purchases of financial instruments such as stocks and bonds. Sales For customer, product, and purchase information. Online Retailers Order Tracking, customized recommendations
6. Cont.. Manufacturing Supply chain management , production of items in factories, inventories of items in warehouses/stores and orders for items. Human Resources Employee records, salaries, tax deductions. Databases touch all aspects of our lives.
7. University database Example Application program examples Add new students, instructors, and courses Register students for courses, and generate class lists Assign grades to students, compute Term grade point averages (TGPA) and generate transcripts
9. Drawbacks of using File system to store data 1. Data Redundancy & Inconsistency- Multiple file formats, duplication of information in different files 2. Difficulty in accessing data Conventional file-systems do not allow needed data to be retrieved in a convenient and efficient manner. Need to write a new program to carry out each new task. 3. Data Isolation Multiple files & formats
10. Cont.. 4. Integrity problems Integrity constraints (e.g., account balance > 0) become “buried” in program code rather than being stated explicitly Hard to add new constraints or change existing ones 5. Atomicity of updates Failures may leave database in an inconsistent state with partial updates carried out Example: Transfer of funds from one account to another should either complete or not happen at all
11. Cont.. 6. Concurrent access by multiple users Concurrent access needed for performance Uncontrolled concurrent accesses can lead to inconsistencies Example: Two people reading a balance (say 100) and updating it by withdrawing money (say 50 each) at the same time 7. Security problems Hard to provide user access to some, but not all, data Database systems offer solutions to all the above problems