1 / 34

Database Management Ch.14-A,B,C,D

Database Management Ch.14-A,B,C,D. FALL 2000 Rob Wolfe. What is data?. da-tum n [L, fr. neut. of datus ] 1 pl. da-ta : something given or admitted esp. as a basis for reasoning or inference 2 pl. da-tums : something used as a basis for calculating or measuring.

morag
Télécharger la présentation

Database Management Ch.14-A,B,C,D

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Database ManagementCh.14-A,B,C,D FALL 2000 Rob Wolfe

  2. What is data? da-tumn [L, fr. neut. of datus] 1pl.da-ta : something given or admitted esp. as a basis for reasoning or inference 2pl.da-tums : something used as a basis for calculating or measuring DIT 2006 - Wolfe

  3. Managing Data • Paper-based record-keeping approach • Personal / Less official data • Still viable • Electronic record-keeping approaches • File systems • Database systems DIT 2006 - Wolfe

  4. File Systems • A file system is a collection of electronic data files that are specifically designed for and around individual applications. • Efficient • Inflexible • Important! - “Not every computerized record-keeping system is a database system.” DIT 2006 - Wolfe

  5. File Systems DF DF DF R L B DIT 2006 - Wolfe

  6. Database Systems • A database systemis a computerized record-keeping system that maintains information and makes it available to multiple users upon demand. [Date] • Requirements • Data model • DBA • DBMS DIT 2006 - Wolfe

  7. Data Modeling ID? Name? • Entity • Attribute • Value • Instance Student Major? Address? Sex? Class? ID: 1234567 Name:Jack Jones Class: 2000 Sex: M Addr: 123 Main Street ... DIT 2006 - Wolfe

  8. Data Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • Table • Field • Data Item • Record • Entity • Attribute • Value • Instance ID: 1234567 Name:Jack Jones Class: 2000 Sex: M Addr: 123 Main Street ... DIT 2006 - Wolfe

  9. Data Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • Table • Field • Data Item • Record • Entity • Attribute • Value • Instance DIT 2006 - Wolfe

  10. Data Modeling • Hierarchical Data Model • Network Data Model • Relational Data Model • Object-oriented Data Model Fields Primary Key Records DIT 2006 - Wolfe

  11. Database Management System • A Database Management System(DBMS) is a piece of software that defines the database structure and performs data manipulation to the records residing in a database • Selection of a DBMS depends on data model and data management environment. • Examples … Access, Oracle, Sybase, DB2, Informix, SQLServer DIT 2006 - Wolfe

  12. Database Administrator • A Database Administrator (DBA) is responsible for … • Data modeling & database establishment • Maintenance of data dictionary • Management and upgrade of DBMS • User support & training • Database system documentation DIT 2006 - Wolfe

  13. When it comes to database systems ... • Remember these two keywords! • Integration • Sharing • These two words make the difference between database systems and file systems! DIT 2006 - Wolfe

  14. Database Systems DBMS B DB DBA R L DIT 2006 - Wolfe

  15. Why Database Systems? • Advantages over traditional (paper-based) record-keeping systems • Compact • Speedy • Less Drudgery • Current • Available DIT 2006 - Wolfe

  16. Why Database Systems? • Advantages over file systems due to integration and sharing through centralized control • Reduced Redundancy • Data integrity (Rid inconsistency) • Standards • Security • Better Communication DIT 2006 - Wolfe

  17. Can you tell them apart? • Database • Database Management System (DBMS) • Database System DIT 2006 - Wolfe

  18. Can I call this a database system? • Microsoft Access • Personal Computer • Single User DIT 2006 - Wolfe

  19. What is a “Data File”? Possible definitions: “A data file is any file that … ” • Contains data • Documents • Spreadsheets • Sounds, Graphics, Videos • Not executable! • Contains information in a uniform format • ID, Name, Phone, etc. • Examples: Inventory, Library Catalog DIT 2006 - Wolfe

  20. File, Records, Fields, and Data Items DIT 2006 - Wolfe

  21. Common Data Types • Numeric • Numbers • Mathematical manipulation implied • Real, Integers, etc. • Character or String • Alphanumeric • Name, description, ID • Date • Logical (Yes or No) • Memo DIT 2006 - Wolfe

  22. Data Modeling • An effective data model helps … • Enter, find, and manipulate data • Understand relationships between entities • Create efficient data structure • Techniques • Show Entities, Relationships, and Cardinality • Entity-Relationship (E-R) Diagrams DIT 2006 - Wolfe

  23. Data Modeling • Entities and Relationships Belongs to Employee Department DIT 2006 - Wolfe

  24. Data Modeling Employee Employee Employee S.S.N. Phone No. Certificate Cardinality ... The number of occurrences that can exist between two record types • One-to-one • One-to-many • Many-to-many DIT 2006 - Wolfe

  25. Is it a good data model? • Query1: Find ID numbers of students in MGT 2006. • Query2: Find Courses that Student 12000 is taking. • Insert: Add Student 32222, William Gates, an MIS major. • Delete: Student 13111 drops MGT 2006, which is the only course she takes. • Update: Student 31111 switches to MIS major. DIT 2006 - Wolfe

  26. Data Models • Hierarchical Data Model • Network Data Model • Relational Data Model • Object-oriented Data Model Course Student DIT 2006 - Wolfe

  27. Hierarchical Data Models Course Instructor Room Time MGT 2006 Barney B214 MWF 06:00 Student ID Name Major Grade 12000 Day, Ken MIS A 13111 Smith, Doris ACC B 15000 Jones, Mary MKT B MKT 1000 Bond B201 MWF 12:00 25000 Brown, James ACC A 31111 Dolk, Sean MKT B LAW 4101 Judy B120 TTH 1:00 12000 Day, Ken MIS B 31111 Dolk, Sean MKT A DIT 2006 - Wolfe

  28. Data Models • Hierarchical Data Model • Network Data Model • Relational Data Model • Object-oriented Data Model Link Nodes Course Student DIT 2006 - Wolfe

  29. Network Data Model A 12000 Day, Ken MIS MGT 2006 Barney B B 13111 Smith, Doris ACC A 15000 Jones, Mary MKT MKT 1000 Bond B 25000 Brown, James ACC B LAW 4101 Judy 31111 Dolk, Sean MKT A Link Nodes DIT 2006 - Wolfe

  30. Data Models • Hierarchical Data Model • Network Data Model • Relational Data Model • Object-oriented Data Model Course Instructor Room Time MGT 2006 Barney B214 MWF 06:00 MKT 1000 Bond B201 MWF 12:00 LAW 4101 Judy B120 TTH 1:00 DIT 2006 - Wolfe

  31. Relational Data Model Course Instructor Room Time MGT 2006 Barney B214 MWF 06:00 MKT 1000 Bond B201 MWF 12:00 LAW 4101 Judy B120 TTH 1:00 Student ID Name Major 12000 Day, Ken MIS 13111 Smith, Doris ACC 15000 Jones, Mary MKT 25000 Brown, James ACC 31111 Dolk, Sean MKT Course Student ID Grade MGT 2006 12000 A MGT 2006 13111 B MGT 2006 15000 B MKT 1000 25000 A MKT 1000 31111 B LAW 4101 12000 B LAW 4101 31111 A DIT 2006 - Wolfe

  32. Software for Data Management • Custom Software (Programming Languages) • File management Software • DBMS • Web-Enabled Software DIT 2006 - Wolfe

  33. Object-Oriented DBMS DIT 2006 - Wolfe

  34. Web-Enabled Tools • Common Gateway Interface (CGI ) allows you to pass requests from the Web browser to the database and back again using programs written in languages such as Perl, C, and Visual Basic. • Web application development tools provide a way to link HTML pages to a database without programming. (E.g., Cold Fusion) DIT 2006 - Wolfe

More Related