Why Study Databases? Databases have incredible value to businesses. Very important technology for supporting operations. Vastly superior to spreadsheets and file processing systems Businesses cannot survive without secure, accessible, and flexible data. Database provide a universal standardized way to store data (in a secure way).
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
Foundation Data Concepts 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 Large Small
Fields Characters “B R E I M E R” form a field A field is an attribute of an entity Last Name Breimer
Records A bunch of fields form a record A record is an entity Last Name Breimer First Name Eric Sex Yes Weight 263
Tables A bunch of records forms a table A table is a group of related entities First NameLast NameSexAge EricBreimerM46 JosephKimM20 AlliePrimoF21
Databases A bunch of tables form a database A database can represent a single business or an entire market Customer Table Product Table Order Table
Databases But, databases are not just a bunch of tables A database also includes relationships between the different tables Customers CIDFNameLNameAddress 508EricBreimer... 509AndrewZych... 510GregSmith... Products PIDDescriptionCost 199Viagra$45.99 200Tooth Paste$2.58 201Hair Gel$5.99 Orders OIDCIDPIDQuantity 001508199500,000 0025082012 0035102011
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. ThingAThingB Relationship ManWoman Married
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 Faculty Student Advises Get Advisement
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. course has a student student takes course Course Student Course Student
How to Model Relationships Customers CIDFNameLNameAddress 508EricBreimer... 509AndrewZych... 510GregSmith... Products PIDDescriptionCost 199Viagra$45.99 200Tooth Paste$2.58 201Hair Gel$5.99 Orders OIDCIDPIDQuantity 001508199500,000 0025082012 0035102011
Find the name and hire date of the manager working on the sales manual project
Traditional File Processing Sucks File Processing: Data is organized, stored, and processed in independent files of data records Sometimes the files are spreadsheets Sometimes they can can even be Word or Text Documents (eeeck!)
Problems of File Processing Data Redundancy – duplicate data requires update to many files Lack of Integration – data stored in separate files hard to combine data Data Dependence – changing the file format requires changing the program…
Database Management Approach Consolidates data records into one CENTRAL database that can be accessed by many different application programs.
Database Management Software (DBMS) Definition: Software that controls the creation, maintenance, and use of databases
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
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
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
Schemas Schema - A description of the database Subschema – describes a subset of the database and which users have access to this subset
Data Definition Language Language Used to describe Schemas and Subschemas Describes relationships between different data Provides a Logical view of the data
Data Dictionary Entry A more detailed description of the data in a database Specifies data types and ranges Assists programmers in understanding the data
Physical vs. Logical DBMS concentrate on Physical access to the underlying tables Concurrency control Query’s Creating/deleting tables
Physical vs. Logical MIS systems are (Logically) interface with a DBMS monthly reports charts automated inquiries
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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