Organizing Data

1. Organizing Data John Sum Institute of Technology Management National Chung Hsing University Introduction to Information Management

2. Data • Data • A necessity for almost any enterprise to carry out its business. Consists of raw facts, and when organized may be transformed into information. • Database • A collection of data organized to meet users’ needs • Database Management System (DBMS) • A group of programs that manipulate the database and provide an interface between the database and the user of the database or other application programs. Introduction to Information Management

3. The Hierarchy of Data Database A collection of integrated and related tables. Table A collection of related records. Record A collection of related fields. Field A group of characters. Character Basic building block of information, represented by a byte. Introduction to Information Management

4. Data Entities, Attributes, and Keys • Entity • A generalized class of people, places, or things (objects) for which data is collected, stored, and maintained. • Attribute • A characteristics of an entity; something the entity is identified by. • Keys • A field or set of fields in a record that is used to identify the record. Entities Customer, Employee Attributes Customer name, Employee name Primary key A field or set of fields that uniquely identifies the record. Introduction to Information Management

5. Keys and Attributes Entities (records) Key Field Attributes Introduction to Information Management

6. The Traditional Approach • The Traditional Approach • Separate files are created and stored for each application program. Introduction to Information Management

7. The Database Approach • The Database Approach • A pool of related data is shared by multiple application programs. Rather than having separate data files, each application uses a collection of data that is either joined or related in the database. Introduction to Information Management

8. The Database Approach Introduction to Information Management

9. Data Modeling and Database Models • Planned Data Redundancy • A way of organizing data in which the logical database design is altered so that certain data entities are combined. • Summary totals are carried in the data records rather than calculated from elemental data. • Some data attributes are repeated in more than one data entity to improve database performance. Introduction to Information Management

10. Data Modeling • Data Model • A map or diagram of entities and their relationships. • Enterprise data modeling • Data modeling done at the level of the entire organization. • Entity-Relationship (ER) diagrams • A data model that uses basic graphical symbols to show the organization of and relationships between data. Introduction to Information Management

11. Attributes Entities Relationship Entity Relationship (ER) Diagram Introduction to Information Management

12. Database Models • Hierarchical Database Model • A data model in which the data is organized in a top-down, or inverted tree structure. • Network Data Model • An expansion of the hierarchical database model with an owner-member relationship in which a member may have many owners. • Relational Data Model • All data elements are placed in two-dimensional tables, called relations, that are the logical equivalent of files. Introduction to Information Management

13. Hierarchical Database Model Introduction to Information Management

14. A Network Data Model Owners Members Introduction to Information Management

15. A Relational Data Model Introduction to Information Management

16. Relational Database Terms • Selecting • Data manipulation that eliminates rows according to certain criteria. • Projecting • Data manipulation that eliminates columns in a table. • Joining • Data manipulation that combines two or more tables. • Linked • Related tables in a relational database together. Introduction to Information Management

17. Linking Data Tables to Answer an Inquiry Description Dept. Number Manager SSN Lastname Hiredate Sales Manual 598 098-40-1370 Fiske 01-05-1985 Introduction to Information Management

18. Logical and Physical Access Paths • Logical Access Path • Application requires information from the DBMS. • Physical Access Path • DBMS accesses a storage device to retrieve data. Introduction to Information Management 25

19. Manipulating Data • Concurrency Control • A method of dealing with a situation in which two or more people need to access the same record in a database at the same time. • Data Manipulation Language (DML) • The commands that are used to manipulate the data in a database. • Structured Query Language (SQL) • A standardized data manipulation language. Introduction to Information Management

20. Structured Query Language Introduction to Information Management

21. Database Output Introduction to Information Management 28

22. Popular DBMS • Microsoft Access • Lotus Approach • Orcale • IBM DB2 • DBMS Selection Criteria • Database size • Number of concurrent users • Performance • Integration • Features • The vendor • Cost Introduction to Information Management

23. Distributed Databases • A database in which the actual data may be spread across several smaller databases connected via telecommunications devices. Introduction to Information Management 30

24. Distributed Databases Introduction to Information Management 30

25. Open Database Connectivity (ODBC) • A set of standards that ensures software written to comply with these standards can be used with any ODBC-compliant database. Introduction to Information Management

26. Data Mining • The automated discovery of patterns and relationships in a data warehouse. Introduction to Information Management 33