data base management system (DBMS)
- 1. NOIDA BRANCH OF CIRC OF ICAI VARISH BAJAJ DATA BASE MANAGEMENT SYSTEM Mr. OM PRAKASH (ITT FACULTY)
- 2. Introduction to DBMS (Database Management Systems) Application program End-user DBMS
- 3. Database Overview Database What, Why, How Evolution of Database File System Data Models Hierarchical Network Relational Entity-Relationship Object-Oriented Web Database
- 4. Database: What Database is collection of related data and its metadata organized in a structured format for optimized information management Database Management System (DBMS) is a software that enables easy creation, access, and modification of databases for efficient and effective database management Database System is an integrated system of hardware, software, people, procedures, and data that define and regulate the collection, storage, management, and use of data within a database environment
- 5. Database Management System Database Systems: Design, Implementation, & Management: Rob & Coronel - manages interaction between end users and database
- 6. Database: Why Purpose of Database Optimizes data management Transforms data into information Importance of Database Design Defines the database’s expected use Avoid data redundancy & ensure data integrity Poorly designed database generates errors Functions of DBMS/Database System Stores data and related data entry forms, report definitions, etc. Hides the complexities of relational database model from the user Enforces data integrity Implements data security management
- 7. Database: How Planning & Analysis Assess Goal of the organization Database environment existing hardware, software, raw data, data processing procedures Identify Database needs what database can do to further the goal of the organization User needs and characteristics who the users are, what they want to do, how they envision doing it Database system requirements what the database system should do to satisfy the database and user needs Design From conceptual design to a detailed system specification Implementation Create the database Maintenance Troubleshoot, update, streamline the database
- 8. Business Rules What Brief, precise, and unambiguous descriptions of operations in an organization Why Enhance understanding & facilitate communication Promote creation of an accurate data model How (sources) Interviews Written documentation Observation
- 9. Database: Data Models Importance Abstraction of complex real-word data structures in relative simple (graphical) representations Facilitate interaction among the designer, the applications programmer, and the end user Basic Building Blocks Entity thing about which data are to be collected and stored Attribute a characteristic of an entity Relationship describes an association among entities Constraint restrictions placed on the data
- 10. Hierarchical Database Background Developed to manage large amount of data for complex manufacturing projects e.g., Information Management System (IMS) IBM-Rockwell joint venture clustered related data together hierarchically associated data clusters using pointers Hierarchical Database Model Assumes data relationships are hierarchical One-to-Many (1:M) relationships Each parent can have many children Each child has only one parent Logically represented by an upside down tree
- 11. Hierarchical Database: Example Database Systems: Design, Implementation, & Management: Rob & Coronel
- 12. Hierarchical Database: Pros & Cons Advantages Conceptual simplicity groups of data could be related to each other related data could be viewed together Centralization of data reduced redundancy and promoted consistency Disadvantages Limited representation of data relationships did not allow Many-to-Many (M:N) relations Complex implementation required in-depth knowledge of physical data storage Structural Dependence data access requires physical storage path Lack of Standards limited portability
- 13. Database Administrator Coordinates all the activities of the database system; the database administrator has a good understanding of the enterprise’s information resources and needs: Database administrator’s duties include: Schema definition Storage structure and access method definition Schema and physical organization modification Granting user authority to access the database Specifying integrity constraints Acting as liaison with users Monitoring performance and responding to changes in requirements
- 14. Structure of a DBMS • A typical DBMS has a layered architecture. • The figure does not show the concurrency control and recovery components. • Each database system has its own variations. Query Optimization and Execution Relational Operators Files and Access Methods Buffer Management Disk Space Management DB These layers must consider concurrency control and recovery
- 15. Overall System Structure indices Statistical data Data files Data dictionary disk storage
- 16. Use of a Database Management System in Design and Application Design Analysis Design Verification Evaluation Synthesis Release Manufacturing Planning Production Control Project Management APPLICATION DBMS Database Management System Graphic Interface Language InterfaceINTERFACE Preliminary- design Analysis Models Detailed Design Design Release Control Fabrication Assembly Info Test / Inspection Database Manufacturing
- 17. Advantages of a DBMS Data independence Efficient data access Data integrity & security Data administration Concurrent access, crash recovery Reduced application development time So why not use them always? Expensive/complicated to set up & maintain This cost & complexity must be offset by need General-purpose, not suited for special-purpose tasks (e.g. text search!)
- 18. Levels of Abstraction • Views describe how users see the data. • Conceptual schema defines logical structure • Physical schema describes the files and indexes used. • (sometimes called the ANSI/SPARC model) Physical Schema Conceptual Schema View 1 View 2 View 3 DB
- 19. Reports and Their Anatomy • Columnar report vs. Tabular report • Report header & footer • Page header & footer • Group header & footer • Detail section • Report Wizard
- 20. Report View Report Header Page Header Detail Section
- 21. Report Design View Report Header Page Header Detail Section Page footer
- 22. Creating a Query Select query Query window views - Datasheet view - Design view - SQL view
- 23. Creating a Query--Selection Criteria • AND condition • OR condition • Relational operators • Between function • NOT function • Wild card
- 24. Creating a Select Query Hands-On Exercise • Open Database • Add Students Table • Create Query • Specify Criteria •Run the Query •Modify Query •Create a Report •View the Report
- 25. Select Query Design View table criteria Run button
- 26. Example: A Simple Query Processing Query in SQL： SELECT CUSTOMER. NAME FROM CUSTOMER, INVOICE WHERE REGION = 'N.Y.' AND AMOUNT > 10000 AND CUTOMER.C#=INVOICE.C Internal Form : ((S SP) Operator : SCAN C using region index, create C SCAN I using amount index, create I SORT C?and I?on C# JOIN C?and I?on C# EXTRACT name field Calls to Access Method： OPEN SCAN on C with region index GET next tuple . . . Calls to file system： GET10th to 25th bytes from block #6 of file #5 Language Processor Optimizer Operator Processor Access Method File System database Language Processor Access Method e.g.B-tree; Index; Hashing DBMS
- 27. Primary Key primary key fields A primary key can consist of more than one field.
- 28. Foreign Key foreign key field primary key field parent tableDirectors Movies child tablerelationship
- 29. The Key • Super Key • Candidate Key • Primary Key • Alternate Key • Secondary Key • Foreign Key
- 30. Super key A super key is a set of one or more attributes which taken collectively. It allow us to identify uniquely an entity instance in the entity set like program and course code. An entity type, its defining attributes and super key (underlined)
- 31. Primary key • A candidate key chosen by the database • designer to act as key is the primary key. • candidate keys, in that case the database • Designer has to designate one of them as a primary key,
- 32. Example
- 33. One-To-Many Relationship • In the one-to-many relationship a loan is associated with at most one customer via borrower, a customer is associated with several (including 0) loans via borrower
- 34. Many-To-One Relationships • In a many-to-one relationship a loan is associated with several (including 0) customers via borrower, a customer is associated with at most one loan via borrower
- 35. Many-To-Many Relationship • A customer is associated with several (possibly 0) loans via borrower • A loan is associated with several (possibly 0) customers via borrower