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Intro-Part 1

Intro-Part 1. Introduction to Database Management: Ch 1 & 2. Important Points. Databases are everywhere Data independence and abstraction Three Schema Architecture DBMS characteristics and Features. Databases are everywhere. What is a database?

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Intro-Part 1

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  1. Intro-Part 1 Introduction to Database Management: Ch 1 & 2

  2. Important Points • Databases are everywhere • Data independence and abstraction • Three Schema Architecture • DBMS characteristics and Features

  3. Databases are everywhere • What is a database? • What is a database management system (DBMS)? • Examples?

  4. Example: University Database How would you do this without a database? What types of challenges would you face?

  5. File-Based System

  6. Data Independence and Abstraction • The major problem with developing applications based on files is that the application is dependent on the file structure. • That is, there is no program-data independence separating the application from the data it is manipulating. • If the data file changes, the code that accesses the file must be changed in the application. • One of the major advantages of databases is they provide data abstraction. • Data abstraction allows the internal definition of an object to change without affecting programs that use the object through an external definition.

  7. Three Schema Architecture

  8. DBMS • A database management system provides efficient, convenient, and safe shared (i.e., multi-user) storage and access to massive amounts of persistent data. • Efficient - Able to handle large data sets and complex queries without searching all files and data items. • Convenient - Easy to write queries to retrieve data. • Safe - Protects data from system failures and hackers. • Massive - Database sizes in gigabytes and terabytes. • Persistent - Data exists after program execution completes. • Shared - More than one user can access and update data at the same time while preserving consistency. • Interrelated – True of relational DBMS.

  9. Common Features of a DBMS • Database Definition: The database is described to the DBMS using a Data Definition Language (DDL). The DDL allows the user to create data structures in the data model used by the database. • Nonprocedural Access: Once a database has been created in a DBMS using a DDL, the user accesses the data using a Data Manipulation Language (DML). The standard DML is SQL. • Application Development: Graphical tools for developing forms and reports using non-procedural access • Procedural language interface: A language that combines nonprocedural access with procedural programming. • Transaction Processing: Perform scheduling of operations and implements concurrency control algorithms. • Database Tuning: Tools to monitor and improve database performance.

  10. University Database

  11. University Database (ERD)

  12. Nonprocedural Access • Query: request for data to answer a question • Indicate what parts of database to retrieve not the procedural details • Improve productivity and improve accessibility • SQL SELECT statement and graphical tools

  13. Graphical Tool for Nonprocedural Access

  14. SQL Examples • Retrieve all products in the database: • SELECT sku, name, desc, inventory FROM product; • Retrieve all products where inventory < 10: • SELECT name, inventory FROM product WHERE inventory < 10; • Insert a new product into the database: • INSERT INTO product VALUES ('12345678','Soap', 'Ivory Soap',100);

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