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Database Management Essentials for Persistent Data Solutions

Explore the key concepts of database persistence, data management systems, object-oriented databases, and client-server applications. Understand the importance of data modeling, schema design, and system scalability in achieving long-term data storage and retrieval efficiency.

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Database Management Essentials for Persistent Data Solutions

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  1. Databases CIS 422

  2. Lifetime of Data • Transient results to the evaluations of expression • Variables involved in procedure activation • Global variables • Dynamically allocated variables • Data that exists between executions • Data that exits between versions • Data that outlives a program

  3. Essentials to Provide Persistence • Object ID • Properties and relationships • Scale of the store • Stability of the store

  4. Marketing Database Engineering DBMS Sales Accounts Employee Inventory Customer Parts Accounting Engineering Parts Customer Marketing Inventory Accounting Accounts Database vs File System

  5. Database • A collection of related data • Represents some aspect of the real world • Is a logically coherent collection of data with some inherent meaning • Is designed, built, and populated with data for a specific purpose.

  6. Database Management Systems • Data • Schema • Program Independence • Views

  7. Motor Vehicle Bus Truck Car Hierarchical Model

  8. Customer Soup Order Network Model

  9. Soup-ID Soup Name Price Address Cust-ID Cust-ID Order-ID Name Soup-ID Phone Qty Relational Model

  10. Database Interface • Approaches • Data Definition Language CREATE TABLE inventory (inventory-number CHAR(20)NOT NULL description CHAR(25)NOT NULL price DECIMAL (9,2) • Data Manipulation Language

  11. Shareability • Transactions • Commit • Abort • Atomicity

  12. Concurrency • Locking • Conservative Locking Policy • Read Locks • Write Locks

  13. Object Oriented vs Traditional • Objects are active components • OO Databases have inheritance • Allow storage in the form of objects

  14. OODBMS - OO Part • The system must support complex objects • Object identity must be supported • Objects must be encapsulated • The system must support types or classes • The system must support inheritance • The system must avoid premature binding • The system will be computationally complete • The system must be extensible

  15. OODBMS - DB Part • It must be persistent, able to remember object state • It must be able to manage very large databases • It must accept concurrent users • It must be able to recover from hardware and software failures • Data query must be simple

  16. OID OID OID Emp# Position Salary Emps ENAME DEPT# Mgr Budget DNAME ddd sss eee Mktg Smith 50,000 E001 1,000,000 D01 …... Complex Objects Job Object OID’s of Employee Objects

  17. Object Data Management GroupModel Parts • Literals • Objects (OID) • system assigned • not dependent on attribute values • conceptual address • Collections

  18. Abstract Types - Interfaces • Inherit signatures of operations • Noninstantiable • Behaviour Inheritance • Supertype must be an interface • Subtype may be interface or class

  19. Classes • Specifies both attributes and behavior • Instantiable • Class Inheritance • supertype must be a class • subtype must be a class

  20. Relationships • Inverses • 1-1 • n-1 • n-m

  21. Persistent Objects • Naming & Extents • Reachablility • Key

  22. Worker calcDeductions calcPay Employee string name string ssn int dependents Salaried double salary Hourly double hours double rate Company Schema 1 1 n 1 office department

  23. Representation interface Worker { method double calcDeductions(); method double calcpay(); }; class Employee : Worker ( extent workers key ssn) { atttribute string name attribute string ssn attribute int dependents relationship Department worksIn inverse Department::hasEmployees relationship Office residesAt inverse Office::houses }

  24. Representation Continued class Salaried extends Employee ( extent salaried) { attribute double salary } class Department ( extent departments key number) { attribute int number attribute string name relationshipset<Employee> hasEmployees inverse Employee::worksIn }

  25. car cost color make model Cost color make model Table-Class Mapping

  26. Employee Customer name address custID empID name address empID name address custID Table-Multiple Classes Mapping

  27. HourlyEmp wage Employee name ssn address SalariedEmp salary name address ssn wage salary Table-Inheritance Classes Mapping

  28. Name DepartmentID Name deparmentID ssn salary Department name departmentID Employee name salary ssn Instance Relationships

  29. Client • Sends message to server • Manages user interface • validate data • dispatch requests • Solution specific logic • GUI

  30. Server • Fulfills the client request • Usually does database access functions • File server • Transaction server • Located separate from client

  31. Basic Characteristicsof Client-Server Apps • Front-end client acts with back-end server • The two tasks have fundamentally different needs • Environment is generally heterogeneous and multivendor • Scalability

  32. Common Components • User Interface • Business Processing • Database Processing

  33. Distributed Processing • Processing divided up between processes • Objects can be distributed and accessed by users across a network

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