Chapter 1 provides a general overview of the nature and purpose of database systems. We explain how the concept of a database system has developed, what the common features of database systems are, what a database system does for the user, and how a database system interfaces with operating systems. | Chapter 1: Introduction Database System Concepts, 6th Ed. ©Silberschatz, Korth and Sudarshan See for conditions on re-use Database Management System (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 Database Applications: Banking: transactions Airlines: reservations, schedules Universities: registration, grades Sales: customers, products, purchases Online retailers: order tracking, customized recommendations Manufacturing: production, inventory, orders, supply chain Human resources: employee records, salaries, tax deductions Databases can be very large. Databases touch all aspects of our lives Database System Concepts - 6th Edition ©Silberschatz, Korth and Sudarshan University Database Example Application program examples Add new students, instructors, and courses Register students for courses, and generate class rosters Assign grades to students, compute grade point averages (GPA) and generate transcripts In the early days, database applications were built directly on top of file systems Database System Concepts - 6th Edition ©Silberschatz, Korth and Sudarshan Drawbacks of using file systems to store data Data redundancy and inconsistency Multiple file formats, duplication of information in different files Difficulty in accessing data Need to write a new program to carry out each new task Data isolation — multiple files and formats Integrity problems Integrity constraints (., account balance > 0) become “buried” in program code rather than being stated explicitly Hard to add new constraints or change existing ones Database System Concepts - 6th Edition ©Silberschatz, Korth and Sudarshan Drawbacks of using file systems to store data (Cont.) Atomicity of updates Failures may leave
