Databases – Introduction to Relational Database Management Systems (DBMS)
Databases – Introduction to Relational Database Management Systems (DBMS)
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Brief-Overview-DBMS
Introduction to "what is a database". Brief overview of DBMS in the context of relational tables and databases.On Github SUNY-Albany-CCI-LearningEncounters / Brief-Overview-DBMS
Databases
Introduction to Relational Database Management Systems (DBMS)
Created by Nic DePaula
What is a database?
"One or more large structured sets of persistent data, usually associated with software to update and query the data. A simple database might be a single file containing many
records, each of which contains the same set of fields where each field is a certain fixed width. "
database. (n.d.). The Free On-line Dictionary of Computing. Retrieved January 24, 2014, from Dictionary.com website:
http://dictionary.reference.com/browse/database
WHAT IS A DATABASE?
"a collection of related tables and other structures"
or
"a self-describing collection of related records"
(Kroenke and Auer (2011), Database Concepts)
Simply put:
a collection of structured or organized data
Database System
Composed of four components:
1) users
2) the database application
3) database management system (DBMS)
4) the database
A (relational) database
For relational databases, emphasis on:
"self-describing" and "related tables"
Self-describing: " a description of the structure of the database is contained within the database itself"
(Kroenke and Auer (2011), Database Concepts)
Related tables: tables have a "relation" within themselves and with other tables. Multiple tables are related by some identifier included in both tables.
The "relation" in Relational Database
A relation is a set of "tuples" that have the same properties or attributes.
In db world a tuple is a set of attribute-value pairs, such as {name:John, age:29}
Image from: http://upload.wikimedia.org/wikipedia/commons/7/7c/Relational_database_terms.svg
Related tables through identifier:
EmployeeTable
empID
last_name
first_name
dept_num
201
Zhang
Jing
20
205
Jung
Mary
20
229
Lee
Michael
10
DepartmentTable
dept_num
dep_nam
dep_location
10
Executive
Building 1
20
Marketing
Building 2
30
Accounting
Building 3
Metadata
Data about the data.
This could be data about the structure of the database, such as: names of tables, names of columns, properties of the fields and so on...
Metadata could also include more information about the origins of the data, such as time of collection, context and others.
Database management System
(DBMS)
A complex software application that enables the creation, processing and management of databases.
Functions of a DBMS
- Create database and tables
- Create supporting structures (eg indexes)
- Read database data
- Modify data
- Maintain database structure
- Enforce rules
- Control concurrency
- Provide security
- Perform backup and recover
Kroenke and Auer (2011), Database Concepts.
Application Programs
Communicate with the DBMS to:
- Create and process forms
- Process user queries
- Create and process reports
- Execute application logic
- Control application
DBMS, such as Access, may include applications that carry out these tasks
Personal vs.Enterprise Database Systems
Personal:
Usually reserved for a defined and small number of data types and uses. For example: lab research on particular results of a certain type of experiments;
database for small retail business; and so on...
Personal Vs. Enterprise Database Systems
Enterprise: More complex system that support large number of tables and operations. Usually will have different applications communicating with the DBMS.
Enterprise Level Database System
Image from: http://management-class.co.uk/public_html/courseware/learner_support/images/ist210image.jpg