Showing posts with label Database. Show all posts
Showing posts with label Database. Show all posts

Sunday, 1 June 2014

Difference Between DBMS and RDBMS



Parameter
DBMS
RDBMS
Acronym for
Data Base Management System
Relational Data Base Management System
Relation
Data is stored in flat file oriented System and no relations are used.
It provides facility to create relation between tables.
Dr. E.F. Codd Rules
Only 3 rules, Out of 12, are followed by DBMS. (from Rule 0 to Rule 12)
Minimum 6 rules, Out of 12, are followed by RDBS. (from Rule 0 to Rule 12)
Data Security
It can’t implement constraints in Tables and has less Security. The ACID (Atomicity, Consistency, Isolation and Durability) property of the database is ensured by Programmer.
It can implement the integrity constraint for the purpose of holding ACID (Atomicity, Consistency, Isolation and Durability) property of the database and is much securing than DBMS.
Generation
3GL
4GL

Users Supported
Single User database, Microsoft Access, Lotus Approach are the best examples of personal database management software.
Multi User Database. E.g. SQL Server can be used my many users on the same time.

Wednesday, 21 May 2014

Difference Between Database and Data Warehouse



Parameter
Database
Data Warehouse
Definition
Organized Collection of Data is called database.
Database of Databases is Called Data Warehouse.
Purpose
It is designed to allow the definition, creation, querying, update, administration of data (Transaction Processing).
It is a relational database that is designed for query and analysis rather than transaction processing.
Data Type
Data stored in Database is up to date.
Current and Historical Data is Stored in Data Warehouse.
Orientation
Transaction Oriented: e.g. Each Transaction of Bank Customer is written to database and is interpreted as Accounting Database.
Subject Oriented: The data in the data warehouse is organized so that all the data elements relating to the same real-world event or object are linked together.

Data Redundancy
Databases are designed to avoid redundancy.
Data Warehouse design is intended to introduce redundancy.

Tuesday, 20 May 2014

Difference Between Data Mining and Machine Learning


Parameter
Data Mining
Machine Learning
Definition
Data mining is a process to extract information from a data set and transform it into an understandable structure for further use.
It is a Technique that concerns the construction and study of systems that can learn from data.
Focus
It focuses on the discovery of unknown properties in the data.
It focuses on prediction, based on known properties learned from training data.
Database Size
It is an automatic or semi-automatic analysis that is performed on large quantities of data.
It is generally performed on small databases to increase accuracy.
Types
Association Rules
Classification
Clustering
Sequential Patterns
Sequence Similarity
Supervised
Un Supervised
Reinforcement

Wednesday, 8 May 2013

Database Management System (DBMS) Interfaces

DBA Interface: This interface is used by the database administrator to create databases, Users, to set system parameters for changing database schema etc. Fig. given below shows admin menu where DBA is can create new user and can assign privileges to him.






























Graphical User Interface: This interface represents database

Tuesday, 7 May 2013

Classification of Database Management System

Database Management System can be classified on several DBMS criteria.

A) On the Basis of Data Models.

Data model is a collection of high level data description that hides many low level storage details. A data Model has following three Components:
1) A Structural Part that consist of a set of rules according to which database is constructed.
2) A Manipulating Part That defines type of operations that are allowed on data.
3) A set of integrity rules that ensures that data is correct.
The Data Models are further divided into Three Categories: 

I) Object Base Data Models: Object based data models defines a database in terms of objects, their properties, and their operations .Objects of same behavior and structure belongs to a class and classes are organized into hierarchies. The operations of each class are specified in terms of predefined procedures called methods. Commonly used object based data models are:
Entity Relationship, Object Oriented, Semantic, Functional

II) Physical Data Models: Physical data models include all data artifacts that are

Sunday, 28 April 2013

DBMS Languages

 DBMS Support a variety of users and provides appropriate languages and interface or each category of users.Here are some languages that are provided by DBMS:
1) Data Definition Language (DDL): This Language is used define data structures and specially database schemas. these statements are used to create, alter, or drop data structures. ALTER ,CREATE ,DROP are some examples of DDL.

2) Storage Definition Language (SDL): This language is used to define internal schema. It defines that what will be the Physical structure of database, How many bites per field will be used, what will be the order of fields, and how records will be accesses etc.

3) View Definition Language (VDL): This language is used to specify user views and their mapping to conceptual schema. It defines the subset of records available to classes of users. It creates virtual tables and the view appears to users like conceptual level.It specifies user interfaces.

4) Data Manipulation Language (DML): It is used at conceptual level and external level and is used to perform operations like Query, Delete Update or Insert.Read Only Queries are also sometimes considered as component of  DML.It modifies the data but not schema or database objects. These languages are further divided into two types:

Saturday, 30 March 2013

Database Normalization

Database Normalization is the process of organizing data in a database by eliminating redundancy and inconsistent dependency. it divides large tables into smaller tables ,which are less redundant , and defines relationships between them.The Main motive is to isolate data so that additions, deletions, and modifications of a field is made in just one table and then propagated through the rest of the database using the defined relationships.

Database normalization uses few rules . Each rule is called a “normal form.” If the first rule is observed, the database is said to be in “first normal form.” If the first three rules are observed, the database is considered to be in “third normal form.” Although other levels of normalization are possible, third normal form is considered the highest level necessary for most applications.

Normalization Form
Description
Example
First normal
form
(1NF)
It is a property of a relation in a relational database. A relation is in first normal form if the domain of each attribute contains only atomic values, and the value of each attribute contains only a single value from that domain
For example, to track an inventory item that may come from two
possible sources, an inventory record may contain fields for Vendor Code 1
and Vendor Code 2.