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Management Information Systems, Sixth Edition

Management Information Systems, Sixth Edition. Chapter 7: Databases and Data Warehouses. Objectives. Explain the difference between traditional file organization and the database approach to managing digital data

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Management Information Systems, Sixth Edition

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  1. Management Information Systems, Sixth Edition Chapter 7: Databases and Data Warehouses

  2. Objectives • Explain the difference between traditional file organization and the database approach to managing digital data • Explain how relational and object-oriented database management systems are used to construct databases, populate them with data, and manipulate the data to produce information • Enumerate the most important features and operations of a relational database, the most popular database model Management Information Systems, Sixth Edition

  3. Objectives (continued) • Understand how data modeling and design creates a conceptual blueprint of a database • Discuss how databases are used on the Web • List the operations involved in transferring data from transactional databases to data warehouses Management Information Systems, Sixth Edition

  4. Managing Digital Data • Businesses collect and dissect data for many purposes • Data can be stored in database format • Easy access and manipulation • Databases have had a profound impact on business • An information industry has been created • Database technology integrated with the Internet has contributed to commerce significantly Management Information Systems, Sixth Edition

  5. The Traditional File Approach • Traditional file approach: no mechanism for tagging, retrieving, or manipulating data • Database approach: provides powerful mechanism for managing and manipulating data • Traditional approach is inconvenient: • Program-data dependency • High data redundancy • Low data integrity • Data redundancy: duplication of data • Data integrity: accuracy of data Management Information Systems, Sixth Edition

  6. The Traditional File Approach (continued) Management Information Systems, Sixth Edition

  7. The Database Approach • Database approach: data organized as entities • Entity: an object about which an organization chooses to collect data, such as: • People • Events • Products • Character: smallest piece of data • A single letter or a digit • Field: single piece of information about entity Management Information Systems, Sixth Edition

  8. The Database Approach (continued) • Record: collection of related fields • File: collection of related records • Database fields can hold images, sounds, video clips, etc. • Field name allows easy access to the data • Database management system (DBMS): program used to: • Build databases • Populate a database with data • Manipulate data in a database Management Information Systems, Sixth Edition

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  10. Management Information Systems, Sixth Edition

  11. The Database Approach (continued) • Query: a message to the database requesting data from specific records and/or fields • Database must be properly secured • Not everyone should have access to all data • Users will have different views of the database, based on the data they are allowed to see Management Information Systems, Sixth Edition

  12. The Database Approach (continued) Database administrator (DBA): the person responsible for managing the database Sets user limits for access to data in the database DBMS is usually bundled with a programming language Management Information Systems, Sixth Edition 12

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  14. Management Information Systems, Sixth Edition

  15. Database Models • Database model: general logical structure • How records stored in the database • How relationships between records are established • Database models differ in: • How records are linked to each other • How users can navigate the database, retrieve records, and create records Management Information Systems, Sixth Edition

  16. The Relational Model • Relational Model: consists of tables • Based on relational algebra • Tuple: record (or row) • Attribute: field (or column) • Relation: table of records • To design a relational database, you must understand the entities to be stored in the database and how they relate • Tables are independent of each other, but can be related to each other Management Information Systems, Sixth Edition

  17. The Relational Model (continued) • Key: a field whose values identify records • Used to retrieve records • Primary key: a field by which records are uniquely identified • Each record in the table must have a unique key value • Composite key: combination of fields that serve as a primary key Management Information Systems, Sixth Edition

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  19. The Relational Model (continued) Management Information Systems, Sixth Edition

  20. The Relational Model (continued) • Foreign key: a field that is common to two tables • Used to link the tables • This field is a primary key in one table and a foreign key in the other • Join table: composite of tables • Two types of table relationships: • One-to-many relationship: one item in a table is linked to many items in the other table • Many-to-many relationship: many items in a table are linked to many items of the other table Management Information Systems, Sixth Edition

  21. The Object-Oriented Model • Object-oriented database model: uses object-oriented approach for the database structure • Encapsulation: combined storage of data and relevant procedures to process it • Allows object to be “planted” in different data sets • Inheritance: the ability to create a new object by replicating the characteristics of an existing (parent) object • Object-oriented databases (ODBs) store data objects, not records Management Information Systems, Sixth Edition

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  23. Relational Operations • Relational operation: creates a temporary subset of a table or tables • Used to create a limited list or a joined table list • Three important relational operations: • Select: a selection of records based on conditions • Project: a selection of certain columns from a table • Join: join data from multiple tables to create a temporary table Management Information Systems, Sixth Edition

  24. Structured Query Language • Structured Query Language (SQL): query language of choice for DBMSs • Advantages of SQL: • It is an international standard • It is provided with most relational DBMSs • It has easy-to-remember, intuitive commands Management Information Systems, Sixth Edition

  25. The Schema and Metadata • Schema: a plan that describes the structure of the database, including: • Names and sizes of fields • Identification of primary keys • Relationships • Data dictionary: a repository of information about the data and its organization • Also called metadata: the data about the data Management Information Systems, Sixth Edition

  26. The Schema and Metadata (continued) • Metadata includes: • Source of the data • Tables related to the data • Field and index information • Programs and processes that use the data • Population rules: what is inserted, or updated, and how often Management Information Systems, Sixth Edition

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  28. Data Modeling • Databases must be carefully planned and designed to meet business goals • Data modeling: analysis of an organization’s data and identification of the data relationships • A proactive process • Develops a conceptual blueprint of the database • Entity relationship diagram: a graphical representation of all entity relationships Management Information Systems, Sixth Edition

  29. Data Modeling (continued) • Entity relationship diagram is composed of: • Boxes: identify entities • Lines: indicate relationship between entities • Crossbars: indicate mandatory fields • Circles: indicate optional • Crow’s feet: identify “many” Management Information Systems, Sixth Edition

  30. Data Modeling (continued) Management Information Systems, Sixth Edition

  31. Data Modeling (continued) Management Information Systems, Sixth Edition

  32. Databases on the Web • Web is dependent on databases • Organizations must link their databases to the Web • Interface between Web and database required • Interface may be programmed in one of several Web programming languages, including: • Java servlets • Active server pages (ASP) • PHP (Hypertext Preprocessor) • Web application program interfaces (APIs) Management Information Systems, Sixth Edition

  33. Databases on the Web (continued) Management Information Systems, Sixth Edition

  34. Data Warehousing • Most data collections are used for transactions • Accumulation of transaction data is useful • Data warehouse: a large repository database that supports management decision making • Typically relational • Data is collected from transactional databases • Data mart: a smaller collection of data focusing on a particular subject or department Management Information Systems, Sixth Edition

  35. From Database to Data Warehouse • Transactional databases are not suitable for business analysis • Contain only current, not historical data • Data warehouse requires large storage capacity: • Mainframe computers are often used • Scalability is an issue • Data warehouses grow continually Management Information Systems, Sixth Edition

  36. Phases in Data Warehousing • Three phases in transferring data from a transactional database to a data warehouse: • Extraction phase: create files from transactional database • Transformation phase: cleanse and modify the data format • Loading phase: transfer files to data warehouse • A properly built data warehouse becomes a single source for all data required for analysis • Data mining and online analytical processing (OLAP) use data in data warehouses Management Information Systems, Sixth Edition

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  38. Summary • Organizations collect vast amounts of data • Database approach has several advantages over traditional file approach • Character: smallest piece of data • Field: made up of multiple characters • Record: collection of related fields • File: collection of related records • Database management system (DBMS): tool to construct databases Management Information Systems, Sixth Edition

  39. Summary (continued) • Relational and object-oriented database models have different advantages • Keys are used to form links among entities • Primary keys are unique identifiers • Object-oriented database maintains objects that contain data and procedures that process it • Structured Query Language (SQL) is an international standard for querying databases • Database designer must construct a schema to construct a database Management Information Systems, Sixth Edition

  40. Summary (continued) • Database designers conduct data modeling and create entity relationship diagrams to plan databases • Many databases are linked to Web • Data warehouses contain huge collections of historical transaction data • Data warehouse requires data extraction, transformation, and loading of transactional data • Invasion of privacy is exacerbated by database technology Management Information Systems, Sixth Edition

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