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Welcome

Welcome. Sixth Lecture for ITEC 1010 3.0 A Professor G.E. Denzel. Agenda. Finish material relevant to Chapter 4 Programming languages Begin discussion of Chapter 5 on data storage and organization. Object Oriented Languages (1). Object-oriented languages (OOL)

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  1. Welcome Sixth Lecture for ITEC 1010 3.0 A Professor G.E. Denzel

  2. Agenda • Finish material relevant to Chapter 4 • Programming languages • Begin discussion of Chapter 5 on data storage and organization

  3. Object Oriented Languages (1) • Object-oriented languages (OOL) • Languages that allow interaction of programming objects, including data elements and the actions that will be performed on them • Note: OOP = object-oriented programming • Encapsulation • The process of grouping items into an object • Polymorphism • A process allowing the programmer to develop one routine or set of activities that will operate on multiple objects

  4. Object Oriented Languages (2) • Inheritance • Property used to describe objects in a group of objects taking on characteristics of other objects in the same group or class of objects • Reusable code • The instruction code within an object that can be reused in different programs for a variety of applications • Examples • Smalltalk, C++, Java

  5. History of Object Orientation • Object-oriented approaches began with development of Simula in the 1960’s • In 1970, Smalltalk was developed • Allowed for easier development of graphical user interfaces (with menus, buttons, windows as objects) • More recently led to other object-oriented languages - C++, Java • Also led to object-oriented databases

  6. Object Oriented Terms • Class Diagram • A graphical model that shows all the classes of objects in the system • For every class (grouping of related objects) there may be specialized subclasses • Sublcasses “inherit” properties of classes above them Car - 4 wheels -engine CLASS IS A Family Car - 4 doors SUBCLASS Sports Car - 2 doors INSTANCE Ferarri Lambargini

  7. Visual Programming Languages • Visual programming languages… • Languages that use a mouse, icons, or symbols on the screen and pull-down menus to develop programs • Examples • Visual Basic • Visual C++ • PC COBOL

  8. Fifth-Generation Languages • 5th generation languages… • Combines rule-based code generation, component management, visual programming techniques, and reuse management • Knowledge-based management • An approach to the development of computer programs in which you do not tell a computer how to do a job, but what you want it to do

  9. CHAPTER 5MANAGING ORGANIZATIONAL DATA AND INFORMATION

  10. Learning Objectives • Discuss traditional data file organization and its problems • Explain how a database approach overcomes the problems associated with a traditional file environment, and discuss the advantages of the database approach • Describe how the three most common data models organize data, and the advantages and disadvantages of each model • Describe how a multidimensional data model organizes data

  11. Learning Objectives(cont’d) • Distinguish between a data warehouse and a data mart • Discuss the similarities and difference between data mining and text mining

  12. Terminology • Database • A collection of integrated and related files • File • 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

  13. Hierarchy of Data Schematic

  14. Hierarchy of data Example Database Class list file (Project database) Department file Tuition file Files 209000111 Johns Francine ITEC SP 208000123 Buckley Bill ITEC O 993045678 Fiske Steven ITMA H (Class list file) Records (Record containing CYIN, last name, first name, Major 993045678 Fiske Steven ITMA H Fields (Last name field) Fiske Characters(bytes) 1000100 (Letter ‘F’ in ASCII)

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

  16. Keys and Attributes Entities(records) Primary Key field Attributes (fields)

  17. The Traditional Approach • The traditional approach… • Separate files are created and stored for each application program Schematic

  18. Application programs Data Files Users Payroll Reports Payrollprograms Invoicing Reports Invoicingprograms Inventorycontrol Inventorycontrolprograms Reports Managementinquiries Reports Managementinquiriesprograms

  19. Traditional File Environment (continued …) • Problems with the file approach • data redundancy - the same piece of information could be duplicated in several places • data inconsistency - the various copies of the data no longer agree • data isolation - difficulty in accessing data from different applications • security - new applications may be added to the system on an ad hoc basis • data integrity not assured - data values must often meet integrity constraints • application/data dependence - the applications and data in computer systems should be independent

  20. 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 Schematic

  21. Database : The Modern Approach Academic Info. Team Data Employee Data Tuition Data Financial Aid Registrar Office Class Programs Student Data Course Data Course Data Registration Data Database Management System Accounting Dept. Accounts Programs Athletics Dept. Sports Programs • Database Management System • provides access to all the data • Example : University administration

  22. Payroll program Reports Payroll data Inventorydata Invoicing Data Otherdata Inventory program Reports Database management system Invoicing program Reports Other programs Reports Database Interface Applications programs Users

  23. Advantages • Improved strategic use of corporate data • Reduced data redundancy • Improved data integrity • Easier modification and updating • Data and program independence • Better access to data and information • Standardization of data access • A framework for program development • Better overall protection of the data • Shared data and information resources

  24. Disadvantages • Relatively high cost of purchasing and operating a DBMS in a mainframe operating environment • Increased cost of specialized staff • Increased vulnerability

  25. Data Modeling and Database Models • Data model • A map or diagram of entities and their relationships • Entity-relationship (ER) diagrams • A data model that uses basic graphical symbols to show the organization of and relationships between data

  26. Example:Entity Relationship (ER) Diagram for a Customer Ordering Database Schematic

  27. Last name Colour Attributes Entities Order First name Name Customer Product 1 N 1:N one-to-many relationship Identificationnumber Identificationnumber

  28. Hierarchical Database Model • Hierarchical database model • A data model in which data are organized in a top-down, or inverted tree structure Schematic

  29. Project 1 Department A Department B Department C Employee 1 Employee 2 Employee 3 Employee 4 Employee 5 Employee 6

  30. Network Data Model • Network data model • An expansion of the hierarchical database model with an owner-member relationship in which a member may have many owners Project 1 Project 2 Department A Department B Department C

  31. Relational Data Model • Relational data model • All data elements are placed in two-dimensional tables, called relations, that are the logical equivalent of files Schematic

  32. Data Table 2: Department Table Data Table 1: Project Table Data Table 3: Manager Table

  33. Relational Database Terminology • 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

  34. Linking Data Tables to Answer an Inquiry Schematic

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