Lesson 1 Introduction to Databases, Information and Data

14% Lesson 1 Introduction to Databases, Information and Data (7 Questions) Competency 4017.1.1: Introduction to Information and Data Explain how data, databases, and data management is used in today's organization Explain what data is and how is it stored Explain the different types of data Define file structures Explain how data was stored and retrieved before the use of database management systems 1.1 Why Databases • Best way to store and manage data • Makes data persistent and shareable in a secure way • Essential for organizations to know information about Customers, Products, Employees, Debtors / Creditors • Helps organizations use data / information as a resource to make decisions 1.2 File Structures • File-Based (Prior to DBMS) o Attempt to computerize old manual filing system o Was easy to retrieve small amounts of information from o As data grew, it became difficult to locate and retrieve information o Retrieval speed depended on file structure and how data was organized within the structure • File types utilized in a file-based system o Flat Files • No internal hierarchy • Plain text or Binary files • Data that is unstructured • Uses a lot of computer memory to access, edit, and rewrite files after use o Heap Files • Unsorted set of records • Uniquely identified by record ID o Allows Heap file to be inserted or deleted using ID o Index Files • File that stores a list of Look Up Field values from data file that includes the location (address) in the data file of the corresponding record • Smaller than the entire record, usually fits in main memory for quick look up • Lists keywords and phrases that are in a particular file • Becomes a pointer to the location in the file where the information can be found when stored with keywords and phrases o Hashed Files • Uses hash functions to decide where records should be placed on a disk • Allows for faster data look up without the use of an index file 1.3 Data versus Information • Data o Data is the Foundation of Information o Consists of Raw Facts not yet processed to reveal meaning o Raw facts / data will need to be transformed to better understand what it is that you have o Must be properly formatted for storage, processing, and presentation • Information o Information is the Bedrock of Knowledge o Produced by Processing Raw Data to reveal its meaning • Processing may be as simple as organizing it to reveal patterns or complex as making forecast / drawing inferences using system statistical modeling o Key to good decision making and business survival is accurate, relevant, and timely information • Knowledge o Information and facts about a specific subject o Implies familiarity awareness and understanding of Information o Key Characteristic is that New Knowledge can be derived from Old Knowledge • Data Management o A discipline that focuses on the proper generation, storage, and retrieval of data o Is it core activity for any business, government agency, service organization, or charity 1.4 Introducing the Database • Database o Shared, integrated computer structure that stores: • End User Data o Raw facts of interest to the end user • Metadata (Also called: A collection of Self-Describing Data) o Data about data through which data is integrated and managed o Describes data characteristics and set of relationships that links data found in the database o Stores information like: • Name of each data element • Type of values (numeric, dates, or text) on each data element • Whether the data element can be left empty o Complements and expands the value and use of the data • Role of the DBMS o An intermediary between user and database o Presents the end user with a single integrated view of data in a database o Receives all application requests and translates them into complex operations o Hides database complexities from the application programs and users o Provides a framework facilitate data quality initiatives o May be written using Visual Basic, NET, JAVA, C#, or through a DBMS utility program • Advantages of a DBMS o Enables data sharing across multiple applications / users o Integrates different user views of data into a single repository o Makes data management more efficient and effective o Improves Data Sharing • Creates an environment in which users have better access two more and better-managed data o Improves Data Security • Provides framework for better enforcement of data / security policies o Better Data Integration • Promotes integrated view of operations and the ability to see data relations or impact actions have in other areas o Minimizes Data Inconsistency • Data Inconsistency exists when different versions of the same data appear in different places • Greatly reduced in a properly designed database o Improves Data Access • Easier to produce quick answers to a query / ad hoc query o Query is a specific request / question o Ad Hoc Query is a “Spur-or-the-Moment” question o Query Result Set is a collection of data rows returned by a query o Improves Decision Making • Better managed, access and quality or data facilitates better decision-making through data quality initiatives o Data Quality is a comprehensive approach to promoting the accuracy, validity, and timeliness of data o Increases End-User Productivity • The availability of data, combined with the tools that transforms data into usable information, empowers end users to make quick informed decisions that make a difference between success or failure • Type of Databases o Number of Users • Single User o Supports one user at a time o Runs on a personal computer o Called a Desktop Database • Multiuser o Supports multiple users at the same time o Workgroup • Used by multiple people at the same time and supports a small number of users (usually fewer than 50) or a specific department o Enterprise • Used by the entire organization and supports many users (more than 50, usually hundreds) across many departments o Location • Centralized o Data located at a single site o Requires well-defined infrastructure o Infrastructure owned / maintained by organization • Distributed o Data distributed across several sites o Requires well-defined infrastructure o Infrastructure owned / maintained by organization • Cloud o Provided by third-party vendors (Microsoft Azure or Amazon AWS) o Vendors, provide defined performance measures (data storage capacity, required throughput, and availability) o As business demands or requirements grow, performance capabilities can be renegotiated with the cloud provider o Type of Data Stored • General Purpose o Wide variety of data used in multiple disciplines • Discipline Specific o Data focused on specific subject areas o Database Use / Time Sensitivity of Information • Most popular way of classifying databases • Operational Database o Supports and reflects critical day-to-day operations that must be recorded accurately and immediately • Transactions (Sales, Payments or Purchases) o Also known as Online Transaction Processing Database (OLTP), Transactional Database or Production Database • Analytical Database o Stores historical data and business metrics for tactical or strategic decision making o End users can perform advanced analysis of data using sophisticated tools • Main components: o Data Warehouse • Specialized data that stores data in format optimized for decision support • Contains historical data obtained from operational databases as well as data from other external sources o Online Analytical Processing (OLAP) • Tools that work together to provide advanced data analysis for retrieving, processing, and modeling data from the data warehouse