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Chapter 4

ADMS 2511 Chapter 4

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Department
Administrative Studies
Course
ADMS 2511
Professor
Cristobal Sanchez- Rodriguez
Semester
Fall

Description
CHAPTER 4: DATA, INFORMATION AND KNOWLEDGE MANAGEMENT 4.1 MANAGING DATA Difficulties in Managing Data • Amount of data increases exponentially over time • Data are scattered and collected by many individuals using various methods and devices • Data is frequently stored in numerous servers and locations and in different computing systems, databases, formats and human and computer languages • Data comes from many sources (internal, personal, external) • Data decays over time • Data security, quality, and integrity are critical Data Life Cycle - Starts with data collection from various sources (internal, personal, external) - Stored in database(s) - Selected data is then processed to fir format of a data warehouse or data mart - Users then access data in warehouse or mart for analysis using data-analysis tools, which look for patterns and with intelligent systems, which support data interpretation. - Ultimately generate knowledge that can be used to support decision making 4.2 DATABASE APPROACH AND DATABASE MANAGEMENT SYSTEMS - Using databases eliminates many problems that arose from previous methods of storing and accessing data - Databases are arranged so that one set of software programs – database management system – provides all users with access to the data they need Hierarchy of Data for a Computer-Based File • Database o File (or table): logical grouping of related records o Record: logical grouping of related fields o Field: small group of words (name) o Byte: a group of 8 bits. A single character. It can be letter, number or symbol o Bit (binary digit): the smallest unit of data a computer can process Designing the Database Data model • Entity (record): is a person, place, thing, or event such as customer, an employee or a product. Record describes an entity • Attribute (field): each characteristic or quality of a particular entity. (customer name, employee number, or product color) • Primary key: Every record in a table must contain at least one attribute/field that uniquely identifies that record so that it can be retrieved, updated or sorted. (student number) • Secondary keys: are other fields that have some identifying information but typically do not identify that record or entity with complete accuracy. (students major) Entity-Relationship Modeling • Database designers plan the database design in a process called entity-relationship (ER) modeling. • ER diagrams consist of entities, attributes and relationships.  Entity classes: entities of a given type. STUDENT, PARKING PERMIT, CLASS  Instance: representation of one particular entity or entity class. (James Smyth, 145897123)  Identifiers: another name for primary keys. Database Management Systems - DBMS: Set of programs that provides users with tools to add, delete, access and analyze data stored in one location - DBMS minimize the following problems:  Data redundancy: same data is stored in many places  Data isolation: applications cannot access data associated with other applications  Data inconsistency: various copies of the data do not agree Maximizes the following issues:  Data security  Data integrity: data meets certain constraints, such as no alphabetic characters in a SIN field  Data independence: applications and data are independent of one another The Relational Database Model - Is based on the concept of 2D tables. - Designed with a number of related tables - Each of these tables contain entities (rows) and attributes (columns) Query Languages - Structured Query Languag
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