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Chapter 7 Database Systems Please discontinue use of cell phone and turn off ringer Succeeding with Technology Basic Data Management Concepts Organizing Data in a Database Database Management Systems Using Database Systems in Organizations Database Trends Managing Databases The Value of Databases Databases and Database Management Systems (DBMS) transform large quantities of data into specific and valuable information for accomplishing some goal. Succeeding with Technology Database Management System (DBMS) A DBMS consists of a group of programs that manipulate the database and provide an interface between the database and the user or the database and application programs. DATABASE Secure Access DBMS Back End Succeeding with Technology Front End Database A collection of data organized to meet user’s needs. File or Table Field (Attribute) Records (Entities) Succeeding with Technology Database Fields Fields are set to hold specific types of data. Succeeding with Technology Database A Database is a collection of files/tables Succeeding with Technology Database Hierarchy Succeeding with Technology Keys and Primary Key Key: A field in a record that is used to identify the record Primary key: A field that uniquely identifies a record A primary key field prevents duplicate records from occurring in a table. Succeeding with Technology Primary Keys Which field would act as the best primary key? Succeeding with Technology Primary Keys Succeeding with Technology Primary Key Succeeding with Technology Simple but Restrictive DBMS Succeeding with Technology The Database Approach to Data Management Succeeding with Technology 7.2 Organizing Data in a Database Key Terms • Relational Model • Data Analysis Succeeding with Technology The Relational Model In a relational database, tables are linked (related) through common fields. Succeeding with Technology Relation Types One-to-many Most typical Makes use of primary key One-to-one Many-to-many Succeeding with Technology Data Analysis Data analysis is a process that involves evaluating data to identify problems with the content of a database. Consider what would happen if CardNumber were not a primary key, and two or more customers had the same CardNumber. Data Integrity refers to the accuracy of the data in a database. GIGO, or Garbage In Garbage Out, refers to the fact that inaccurate data entered in a database will result in inaccurate information produced from the database. Succeeding with Technology 7.3 Database Management Systems Key Terms • • • • • Data Integrity GIGO Schema Data Dictionary SQL Succeeding with Technology Creating a Database A schema is an outline of the logical and physical structure of the data and relationships among the data in the database. Succeeding with Technology Creating a Database A data dictionary provides a detailed description of all data used in the database. Succeeding with Technology Database Strengths The power of a database and DBMS lies in the user’s ability to manipulate the data to turn up useful information. Data can be sifted, sorted and queried through the use of data manipulation languages. Succeeding with Technology Data Manipulation Language A Data Manipulation Language (DML) is a specific language provided with the DBMS that allows people and other database users to access, modify, and make queries about data contained in the database, and to generate reports. Structured Query Language (SQL): The most popular DML. SELECT * FROM EMPLOYEE WHERE JOB_CLASSIFICATION = ‘C2” Succeeding with Technology 7.4 Using Database Systems in Organizations Key Terms • Data Warehouse • Data Mining Succeeding with Technology The data deluge… The Machinery Moves on: Moore’s law: processing “capacity” doubles every 18 months : CPU, cache, memory It’s more aggressive cousin: Disk storage “capacity” doubles every 9 months The Demand is exploding: Every business is an eBusiness Scientific Instruments and Moore’s law Government The Internet – the ubiquity of the Web The Talent Shortage Succeeding with Technology Data Stores Data Warehouse: A database that holds important information from a variety of sources. Data Mart: A small data warehouse, often developed for a specific person or purpose. Data Mining: the process of extracting information from a data warehouse. “Connecting the dots” Succeeding with Technology Databases & Data Warehouses Operational Databases Succeeding with Technology What Is a Hypercube? Create multi-dimensional “cubes” of information that summarize transactional data across a variety of dimensions. OLAP vs. OLTP Succeeding with Technology What is Data Mining? Finding interesting structure in data Structure: refers to statistical patterns, predictive models, hidden relationships Interesting: ? Examples of tasks addressed by Data Mining Predictive Modeling (classification, regression) Segmentation (Data Clustering ) Affinity (Summarization) relations between fields, associations, visualization An Example Succeeding with Technology Data Mining and Databases Many interesting analysis queries are difficult to state precisely Examples: which records represent fraudulent transactions? which households are likely to prefer a Ford over a Toyota? Who’s a good credit risk in my customer DB? Yet database contains the information good/bad customer, profitability did/did not respond to mailout/survey/... Succeeding with Technology Example: market basket Transactions {Bread, Milk} {Bread, Diapers, Beer, Eggs} {Milk, Diapers, Beer, Cola} {Bread, Milk, Diapers, Beer} {Bread, Milk, Diapers, Cola} What pattern can you see? Succeeding with Technology A more systematic approach: a “Decision Tree” All 1615 patients Split # 1: Age Systolic BP “terminal node” Succeeding with Technology Visualization is Important Factory food example from this week’s New York Times Succeeding with Technology The myths… Companies have built up some large and impressive data warehouses Data mining is pervasive nowadays Large corporations know how to do it There are tools and applications that discover valuable information in enterprise databases Succeeding with Technology The truths… Data is a shambles, most data mining efforts end up not benefiting from existing data infra-structure Corporations care a lot about data, and are obsessed with customer behavior and understanding it They talk a lot about it… An extremely small number of businesses are successfully mining data The successful efforts are “one-of”, “lucky strikes” Succeeding with Technology