Download Mar10IntroDB

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project

Document related concepts

Serializability wikipedia , lookup

Microsoft Access wikipedia , lookup

Microsoft SQL Server wikipedia , lookup

IMDb wikipedia , lookup

Oracle Database wikipedia , lookup

Entity–attribute–value model wikipedia , lookup

Open Database Connectivity wikipedia , lookup

Extensible Storage Engine wikipedia , lookup

Ingres (database) wikipedia , lookup

Microsoft Jet Database Engine wikipedia , lookup

Concurrency control wikipedia , lookup

Database wikipedia , lookup

Relational model wikipedia , lookup

Clusterpoint wikipedia , lookup

ContactPoint wikipedia , lookup

Database model wikipedia , lookup

Transcript
INFS215
Introduction to Databases
Subash C. Biswas
Questions






What is a database?
Why a database is so important?
What are the basic components and types of
databases?
What is an entity, attribute, identifier,
relationships, cardinality (min & max)?
What is referential integrity?
What is an ERD?
Basic Concepts
People
Data
(raw)
Hardware
Software
Procedure
Data
Data
(Information)
Components of A Database
System
Application Programs

Functions:





Create and process forms
Create and transmit queries
Create and process reports
Execute application logic
Control application
DBMS



DBMS: Database Management System
Functions:
 Create database, tables, and supporting structures
 Read and update database data
 Maintain database structures
 Enforce rules
 Control concurrency
 Provide security
 Perform backup and recovery
Example: Oracle, DB2, Microsoft Access,
SQL Server
Database


Database is a self-describing collection of related records
or tables
Components:
 User Data
 Metadata: data about the structure of a database
 Indexes and related structures
 Stored procedures: program modules stored within the
database
 Triggers: a procedure that is executed when a particular
data activity occurs
 Application metadata: data describing application
elements such as forms and reports
Types of Database

Personal database


Workgroup database


1 user; < 10 MB
< 25 users; < 100 MB
Organizational database


Hundreds to thousands users
>1 Trillion bytes, possibly several databases
Example:
Organizational Database
Binary Relationships



1:1
1:N
N:M
Domains



A domain is a named set of values that an attribute can
have
It can be a specific list of values or a pre-defined data
characteristic, e.g. character string of length less than 75
Domains reduce ambiguity in data modeling and are
practically useful
Data Types

Standard data types


Char for fixed-length character
VarChar for variable-length character



It requires additional processing than Char data
types
Integer for whole number
Numeric
Normalization



Normalization eliminates modification anomalies
 Deletion anomaly: deletion of a row loses information
about two or more entities
 Insertion anomaly: insertion of a fact in one entity cannot
be done until a fact about another entity is added
Anomalies can be removed by splitting the relation into
two or more relations; each with a different, single theme
However, breaking up a relation may create referential
integrity constraints
Intersection Tables