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Database Concepts: Foundation, Large Databases, Relationships, and Queries

This chapter explores the importance of studying databases for businesses, introduces foundational data concepts, explains the structure and components of databases, discusses various types of relationships between entities, and compares traditional file processing with database management approach.

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Database Concepts: Foundation, Large Databases, Relationships, and Queries

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  1. 0 Chapter 5 Database Concepts

  2. Why Study Databases? • Databases have incredible value to businesses. • Very important technology for supporting operations. • Vastly superior to file processing systems • Businesses cannot survive without quality data about their • internal operations and • external environment.

  3. Foundation Data Concepts Abstract Concepts • Entity – person, place, object or event – stored as a record or a table row • Attribute – characteristic of an entity – stored as field or table column

  4. Foundation Data Concepts Large Database Concepts • Database – a collection of related tables • Tables – a collection of related records – collection of related entities • Record – collection of fields (table row) –represents an entity • Field – collection of characters (table column) – represents an attribute • Character – single alphabetic, numeric or other symbol Small

  5. Fields • Characters “B R E I M E R” form a field • A field is an attribute of an entity

  6. Records • A bunch of fields form a record • A record is an entity

  7. Tables • A bunch of records forms a table • A table is a group of related entities

  8. 0 Databases • A bunch of tables form a database • A database can represent a single business or an entire market

  9. 0 Databases • But, databases are not just a bunch of tables • A database also includes relationships between the different tables

  10. 0 Chapter 5 Relationships & Queries in Databases

  11. ThingA ThingB Relationship Man Woman Married Types of Relationships One to One • Examples? • Analysis Technique • Consider ThingA and ThingB • Can ThingA be related to more than one ThingB? • Can ThingB be related to more than one ThingA? • If the two answers are NO, then it is a one to one relationship.

  12. Student Faculty Student Student Advises Get Advisement Types of Relationships One to Many • Examples? • Analysis Technique • Consider ThingA and ThingB • Can ThingA be related to more than one ThingB? • Can ThingB be related to more than one ThingA? • If only one answer is yes, then you have a one to many relationship

  13. Student Course Student Student Course course has a student Student student takes course Types of Relationships Many to Many • Examples? • Analysis Technique • Consider ThingA and ThingB • Can ThingA be related to more than one ThingB? • Can ThingB be related to more than one ThingA? • If the answers are yes and yes, then the relationship is many to many.

  14. How to Model Relationships

  15. Find the name and hire date of the manager working on the sales manual project

  16. Traditional File Processing Sucks File Processing: • Data is organized, stored, and processed in independent files of data records

  17. Problems of File Processing • Data Redundancy – • duplicate data requires update to many files • Lack of Integration – • data stored in separate fileshard to combine data • Data Dependence – • changing the file format requires changing the program…

  18. Database Management Approach • Consolidates data records into one CENTRAL database that can be accessed by many different application programs.

  19. Database Management Software (DBMS) Definition: • Software that controls the creation, maintenance, and use of databases

  20. DBMS Software Components • Database Definition • Language and graphical tools to define entities, relationships, integrity constraints, and authorization rights • Application Development • Graphical tools to develop menus, data entry forms, and reports

  21. DBMS Software Components • Transaction Processing • Controls to prevent interference from simultaneous users and • Controls to recover lost data after a failure • Database Tuning • Tools to monitor and improve database performance

  22. Database Interrogation Definition: • Capability of a DBMS to report information from the database in response to end users’ requests • Query Language – allows easy, immediate access to ad hoc data requests • Report Generator - allows quick, easy specification of a report format for information users have requested

  23. Natural Language vs. SQL Queries

  24. Schemas Schema - A description of the database Subschema – describes a subset of the database and which users have access to this subset

  25. Data Definition Language • Language Used to describe Schemas and Subschemas • Describes relationships between different data • Provides a Logical view of the data

  26. Data Dictionary Entry • A more detailed description of the data in a database • Specifies data types and ranges • Assists programmers in understanding the data

  27. Physical vs. Logical • DBMS concentrate on Physical access to the underlying tables • Concurrency control • Query’s • Creating/deleting tables

  28. Physical vs. Logical • MIS systems are (Logically) interface with a DBMS • monthly reports • charts • automated inquiries

  29. Application Development • Today, even non-technical staff can use tools to build little programs that use a database. • Database Management Systems have all kinds of tools to develop custom application programs and interfaces. • Example: The College’s MIS (Banner) is actually an application built on top of a Oracle Database.

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