DB week 1.pdf

Introduction to Database Systems 62153 Jeenan Altawaty [email protected] Outline Traditional Database Applications New Applications of Database Systems What is Database? What is Data? Database Management System (DBMS) Database Building How to...

Introduction to Database Systems 62153 Jeenan Altawaty [email protected] Outline Traditional Database Applications New Applications of Database Systems What is Database? What is Data? Database Management System (DBMS) Database Building How to Design A Database Application? References Elmasri, Ramez, and Shamkant B. Navathe. "Fundamentals of Database Systems 7 th Edition." (2017). (Book) An Introduction to Database Systems, 8th Edition, C J Date (Book). D. Petković, Microsoft SQL Server 2019: a Beginner’s Guide, 7th Edition, McGraw-Hill. (Book) Traditional Database Applications Database and Database systems encounter with most aspects and activities in our lives. Traditional database applications can be textual or numeric. We can find it in bank, airline reservations, hotels, computerized library catalog. New Applications of Database Systems Big Data: Social media Web sites, such as Facebook, Twitter, among many others, has required the creation of huge databases that store nontraditional data, such as posts, tweets, images, and video clips. New types of database systems, often referred to as big data storage systems, or NOSQL systems, have been created to manage data for social media applications. Multimedia Databases Geographic information systems (GISs) Data warehouses and online analytical processing (OLAP) systems are used in many companies to extract and analyze useful business information from very large databases to support decision making Real-time and active database technology is used to control industrial and manufacturing processes. What is Database? A database is a collection of related data. Data, means known facts that can be recorded and that have implicit meaning. What is Data? Data is unorganized information, that is processed to make it meaningful. It can consist of Facts, observations, perceptions, Numbers, characters, symbols, Images or a mix of any of these. Data can be categorized by the level and rigidity of its structure. Data can be structured, semi-structured or unstructured. Introduction. A database has the following implicit properties: A database represents some aspect of the real world, sometimes called the miniworld or the universe of discourse (UoD). Changes to the miniworld are reflected in the database. A database is a logically coherent collection of data with some inherent meaning. A random assortment of data cannot correctly be referred to as a database. A database is designed, built, and populated with data for a specific purpose. It has an intended group of users and some preconceived applications in which these users are interested Database Management System (DBMS) DBMS is a computerized system that enables users to create and maintain a database. The DBMS is a general-purpose software system that facilitates the processes of defining, constructing, manipulating, and sharing databases among various users and applications. Database Building Defining a database involves specifying the data types, structures, and constraints of the data to be stored in the database. The database definition or descriptive information is also stored by the DBMS in the form of a database catalog or dictionary; it is called meta-data. Constructing the database is the process of storing the data on some storage medium that is controlled by the DBMS. Manipulating a database includes functions such as querying the database to retrieve specific data, updating the database to reflect changes in the miniworld, and generating reports from the data. Database Building con… Sharing a database allows multiple users and programs to access the database simultaneously An application program accesses the database by sending queries or requests for data to the DBMS. Database Building con… Other important functions provided by the DBMS include protecting the database and maintaining it over a long period of time. Protection includes system protection against hardware or software malfunction (or crashes) and security protection against unauthorized or malicious access. A typical large database may have a life cycle of many years, so the DBMS must be able to maintain the database system by allowing the system to evolve as requirements change over time To complete our initial definitions, we will call the database and DBMS software together a database system. Example: University Database University Database Building To define this database, we must specify the structure of the records of each file by specifying the different types of data elements to be stored in each record. We must also specify a data type for each data element within a record. To construct the UNIVERSITY database, we store data to represent each student, course, section, grade report, and prerequisite as a record in the appropriate file. University Database Building con… Database manipulation involves querying and updating. Examples of queries are as follows: Retrieve the transcript—a list of all courses and grades—of ‘Smith’ List the names of students who took the section of the ‘Database’ course offered in fall 2008 and their grades in that section List the prerequisites of the ‘Database’ course Examples of updates include the following: Change the class of ‘Smith’ to sophomore Create a new section for the ‘Database’ course for this semester Enter a grade of ‘A’ for ‘Smith’ in the ‘Database’ section of last semester How to Design A Database Application? Design of a new application for an existing database starts with a phase called requirements specification and analysis. Then, these requirements are documented in detail and transformed into a conceptual design. The design is then translated to a logical design that can be expressed in a data model implemented in a commercial DBMS. The final stage is physical design, during which further specification are provided for storing and accessing the database.