Welcome to lesson one of module two on Introduction to Databases and Database Management Systems. I'm going to start with a very simple question that I want you to think about throughout this lesson. What databases have you experienced or interacted with today? You have two objectives in this lesson today. I want you to define in your own words, base on the lecture today, some basic terminology and characteristics of business databases. I want you to apply the vocabulary and characteristics to describe a database that you have recently experienced or interacted with. Now let me motivate this lesson and really the entire course by talking about the role of databases and database technology in organizations. Databases provide vital support for the daily operations and decision making in organizations. Daily operations such as taking orders, making reservations and paying an employee. Decision making tasks such as resolving customer complaints, choosing suppliers and deciding on the location of a new store. Database Management Systems or DBMSs are the enabling tools to create and utilize database in organizations. Database management technology is a major part of the software industry with revolutionary evolvement over 40 years. This evolvement continues today. Databases management technology provides the foundation to manage long-term memory of organizations. Memory about customers, employees, orders, products and other vital entities. A very large part of your motivation is that the database field provides exciting and challenging employment opportunities. These employment opportunities are partially due to that dynamic nature of the database field with continuing innovation. You will find many opportunities to work in the database field, both with the foundation of skills in this course, as well as with the advanced skills and knowledge of other courses, in the data warehouse for business intelligence specialization. Let me begin with some basic vocabulary. Most organizations have a flood of data. Far too much data to deal with. The proliferation of websites, electronic commerce and mobile computing has greatly multiplied the amount of data that an organization must manage. Data are raw facts coming in basically two varieties. Conventional facts are names, addresses, dates of birth, interest rates, sales amounts and so on. Conventional raw facts usually involve numbers and texts that are encountered in everyday speech. Unconventional facts, once thought as media, separate from conventional facts due to the advances in digital capture and manipulation of media, unconventional facts such as images shot on a cellphone, maps, engineering drawings, product videos, fingerprints and web pages are now considered data. In this course we'll focus on conventional facts, but indeed database management technology manages both conventional and non-conventional facts. We'll be focusing on the transformations that convert data to information for decision-making. Raw facts need interpretation, combination, formatting etc., to be used for decision-making. The transformation from data to information may be as simple as formatting a number with currency symbols and commas. The word database is a very generic word. In this course, I will use database in a more specific context, the context that businesses think about databases. There are three essential characteristics that are important. The first characteristic is persistency. Denoted by the image of data storage devices, a magnetic disk and flash drive. Persistency means that data lasts longer than the state of a computer memory when a computer shuts down. Organizations need reliable long-term memory to operate successfully. The second major characteristic is inter-related. Businesses must remember customers, employees, products, orders, courses, shipments and other vital entities. But businesses must also remember relationships among entities such as what orders have been placed by a customer, what products have been shipped, and what students have enrolled in a course. The third essential characteristic is that databases are shared with many applications using the database, and many users simultaneously interacting with the database. For example, many customers may be simultaneously making airline reservations, ordering products and applying for a position. The database may support many applications such as orders, shipments, accounting and customer service. Now I want you to pick these three characteristics. Persistent, inter-related, and shared in an important example, a database to support the operations and decision-making in a university. If you have taken university courses, you have interact with the university database. If not, you have been enrolled in K-12, you've interacted with a similar database. The entities in an organization should remember in this database are students, faculty, courses, offerings of courses and enrollments. Remembering these entities is not enough though. The relationships among these entities are also vital to remember over time. Faculty teaching course offerings, students enrolling in course offerings, offerings schedule of courses are some of the important relationships that must be remembered over time. A university database supports a variety of applications such as registration, grade recording, assignment of faculty to course offerings and scheduling of courses. Many students, perspective students, faculty and administrators can be using the database simultaneously. So in this simple example, we have seen the three essential characteristics of persistent, inter-related and shared by multiple users and usages. Now I want to show you a diagram to depict the second characteristic, inter-related. This diagram is known as an Entity Relationship Diagram or ERD for short. The details are not important here. We will study the details later in the course so that you can create ERDs and understand ERDs created by others. What is important here is that the inter-related characteristic is realized by a complex diagram showing entities, depicted as rectangles and relationships, depicted as lines connecting the rectangles. Th diagram for a real university database might fill an entire hall with hundreds of rectangles and connecting lines. A very complex diagram that must be carefully planned, designed and studied. Now let me summarize lesson one of module two. Databases and database technology are vital to modern organizations supporting both the daily operations and decision-making. Databases support daily operations through electronic commerce such as product ordering and batch operations, such as preparation of bills for a subset of customers. Databases support decision making such as resolving customer complaints, choosing suppliers and deciding on locations for new stores. Database technology enables organizations to develop and deploy databases. In this course, the focus will be on databases for daily operations. In the other courses of the specialization, the focus will be on databases for business intelligence. These databases are known as data warehouses. This course will also emphasize conventional structured data such names, addresses, dates and amounts. Now I want you to think about databases that you've interacted with, and the essential characteristics of persistency, inter-related and shared.
