Chapter 1 Database System.pdf

8/14/2024 ICS2607 INFORMATION MANAGEMENT Chapter 1. Database Systems Instructor: Mr. Francis Noel I. Alarcon, LPT, MS 1...

8/14/2024 ICS2607 INFORMATION MANAGEMENT Chapter 1. Database Systems Instructor: Mr. Francis Noel I. Alarcon, LPT, MS 1 Terminology: Data VS Information Data Raw facts Have yet to be processed Information Processed raw data to something that is useful to the user. Knowledge The body of information and facts about a specific subject 2 1  8/14/2024 Why do we need Databases? From birth to death, every person has come across a variety of data and information throughout there lives. Databases are need to store and manage data that is vast and varied Social media, Lazada, Online Games all of these uses a database 3 Practical application of a Database Have you experience searching for an item in Shopee or Lazada and then seeing a suggestion in Facebook to buy the said item? Have you experience searching for something in Google and then when you visit YouTube there are video suggestions ? Have you checked your recent google activities? 4 2  8/14/2024 Terminology: Database Database A shared, integrated computer structure that houses a collection of related data. A database contains two types of data: end-user data (raw facts) Metadata 5 Terminology: Database Metadata Data about data; that is, data about data characteristics and relationships. For example, the metadata component stores information such as the name of each data element, the type of values (numeric, dates, or text) stored on each data element, and whether the data element can be left empty 6 3  8/14/2024 Terminology: Database management System Database management system (DBMS) A collection of programs that manages the database structure and controls access to the data stored in the database. In a sense, a database resembles a very well-organized electronic filing cabinet in which powerful software (the DBMS) helps manage the cabinet’s contents. 7 Advantage of a Database management System Improved data sharing Improved data security Better data integration Minimized data inconsistency Improved data access Improved decision making Increased end-user productivity 8 4  8/14/2024 Types of Databases – Number of users Single-user database A database that supports only one user at a time. Desktop database A single-user database that runs on a personal computer. 9 Types of Databases – Number of users Multiuser database A database that supports multiple concurrent users. Workgroup database A multiuser database that usually supports fewer than 50 users or is used for a specific department in an organization. Enterprise database The overall company data representation, which provides support for present and expected future needs. 10 5  8/14/2024 Types of Databases – Location Centralized database A database located at a single site. Distributed database A logically related database that is stored in two or more physically independent sites. Cloud database A database that is created and maintained using cloud services, such as Microsoft Azure or Amazon AWS. 11 Types of Databases – Type of data stored General-purpose database A database that contains a wide variety of data used in multiple disciplines. Discipline-specific database A database that contains data focused on specific subject areas. 12 6  8/14/2024 Types of Databases – Data usage Operational database A database designed primarily to support a company’s day-to-day operations. Also known as a transactional database, OLTP database, or production database. Analytical database A database focused primarily on storing historical data and business metrics used for tactical or strategic decision making. 13 Terminology: Structured Data Unstructured Data Data that exists in its original, raw state; that is, in the format in which it was collected. Structured Data Data that has been formatted to facilitate storage, use, and information generation. 14 7  8/14/2024 Database design Database design It refers to the activities that focus on the design of the database structure that will be used to store and manage end-user data. A database that meets all user requirements does not just happen; its structure must be designed carefully 15 Data Redundancy Data redundancy It exists when the same data is stored unnecessarily at different places. Poor data security Data inconsistency Data-entry errors Data integrity problems 16 8  8/14/2024 Data Anomalies Data anomaly It develops when not all of the required changes in the redundant data are made successfully. Update anomalies If agent Leah F. Hahn has a new phone number, it must be entered in each of the CUSTOMER file records in which Ms. Hahn’s phone number is shown. In this case, only four changes must be made. In a large file system, such a change might occur in hundreds or even thousands of records. Clearly, the potential for data inconsistencies is great. 17 Data Anomalies Data anomaly It develops when not all of the required changes in the redundant data are made successfully. Insertion anomalies If only the CUSTOMER file existed and you needed to add a new agent, you would also add a dummy customer data entry to reflect the new agent’s addition. Again, the potential for creating data inconsistencies would be great. 18 9  8/14/2024 Data Anomalies Data anomaly It develops when not all of the required changes in the redundant data are made successfully. Deletion anomalies If you delete the customers Amy B. O’Brian, George Williams, and Olette K. Smith, you will also delete John T. Okon’s agent data. Clearly, this is not desirable. 19 20 10  8/14/2024 Terminology: Database Environment Database system It refers to an organization of components that define and regulate the collection, storage, management, and use of data within a database environment. Five components Hardware Software People Procedure Data 21 DBMS Functions Data dictionary management Data storage management Data transformation and presentation Security management Multiuser access control Backup and recovery management Data integrity management Database access languages and application programming interfaces Database communication interfaces 22 11  8/14/2024 Database VS Spreadsheet While a spreadsheet allows for the manipulation of data in a tabular format, it does not support even the most basic database functionality such as support for self-documentation through metadata, enforcement of data types or domains to ensure consistency of data within a column, defined relationships among tables, or constraints to ensure consistency of data across related tables. Most users lack the necessary training to recognize the limitations of spreadsheets for these types of tasks 23 Disadvantage of a Database management System Increased costs Management complexity Maintaining currency Vendor dependence Frequent upgrade/replacement cycles 24 12  8/14/2024 Database Career Opportunities 25 13