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Thursday, 20 August 2015

Data base and oracle overview



Hi friends, this is sunny kumar.............


we have already discussed about database and oracle, but we have lefted some topics. now m going to covering all that topics here. thiis post is something like Backup post that related to older post.


Database: A database is a collection of interrelated data and typically stored in disk. A databsae has different types that is give here.

DBMS
HDBMS 1970s
NDBMS
RDBMS 1980s
ORDBMS 1990s
OODBMS

This level shows that innovation of Database in mannerd way.

* HDBMS and NDBMS is an outdated system that is not in use yet. Evey organization adopted RDBMS concept.

What is RDBMS ?
RDBMS stands for Relational Database Management. In RDBMS Data organized in table format. Dr. E.F CODD introduced RDBMS concept.he is also known as father of RDBMS. He purposed 12 rules. these rules is known as CODD rules. A DBMS satisfies all CODD rules is called pure RDBMS, but no one satisfies all CODD rules. Oracle satisfies highly 11 1/2.


Difference between DBMS and RDBMS?
Actually there is no matter to ask differences between DBMS and RDBMS. Beacuse RDBMS follows all DBMS properties. It is also a DBMS software where data organized in form of tables.

we will discuss CODD Rules in latter post.........

List of RDBMS Software
Oracle
SQL Server
My Sql
DB2
Teradata
e.t.c

What is ORDBMS?
Object Relational Database Management System. It is the combination of OOPS+RDBMS. where OOPS is for reausability purpose. Now the major Difference between RDBMS and ORDBMS is, RDBMS does't Supports resuability wehere as ORDBMS supports Resuability. It uses UDT, that means User defined types. let's see an example that maximize concept.

In RDBMS

emp(emp_no, emp_name, h_no, street, city state)
customer(cust_id, cust_name, h_no, street, city, state )

in this case four variables are repeated and takes much momery and time to execute.

IN ORDBMS

create a UDT:- ADDR(h_no, street, city state)
emp(emp_no, emp_name, addr)
customer(cust_id, cust_name, addr)
in this case only one variable is repeated. so that this is more flexiable.


what is OODBMS?
This is completely based on OOPS concepts and data stored in an objects. Derby, NoSQL supports OODBMS Features.


Life Cycle Of Database
There are different steps involved to develop a database. these steps are also called phases.
Analysis
design
Development
Testing
Implementation
Maintainance


Analysis: this phase is used to gather information about project. here analyst communicates with end users and customers to gather information.

Design: In this phase Database designer comes in picture. their role is to normalize data and create E-R digram. this is much important phase you anybody want to make reliable and robust database. let's see an example that easliy define how it is important.

emp

emp_no emp_name Dept_name
1 Sunny DBA
2 Pankaj manager
3 Kavita Manager
4 Deepak Programmer


in this table, latter if we want to change department name managerr to analyst then we need to modify two rows. this gonna be hectic if database is large. so we need to create table like this

Table
emp_no emp_name Dept_no
1 Sunny 11
2 Pankaj 22
3 Kavita 22
4 Deepak 33


table
Dep_name dep_no
DBA 11
manager 22
programmer 33

in this case we need too modify only one row to change department name...


Development: This is very important phase where database is developed by Database developer and DBAs. they use any RDBMS Software to develop any database. their works are already discussed in previous post that's why m not including here.

Testing: There is a testing department known as QA(Quality Assurance). they will check all the queries and command that provide right output or not.

Implementation: Implementation is nothing but moving datavase development phase to production. here database is available for user and customers and for specified resources.

Maintainance: it just modification, error correcting phase if demand.




Version and their features of Oracle

ver 1 Introduced by RSI(Relational Software Inc.)
ver 2 Company name changed by Oracle Corporation.
ver 3
ver 4 Supports commit and Rollback command.
ver 5 Supports Client Server Architecture.
ver 6 finincial Application built on oracle.
ver 7 varchar2 datatypes, stored procedures, Triggers, functions, Packages.
ver 8 table partitions, User Defined Types, LOBs(large objects)
ver 8i Heirarchal Queries, SQLJ(SQL Java), XML.
ver 9i Insert All, Merge, Timestamp datatype, OLAP Features,Ansi Joins, Case statement
ver 10g Flash Back, Regular Expression
ver 11g Virtual Columns, follows clause, compund triggers
ver 12c Identity columns, Top N Rows.


From 12c onwards oracle is cloud database.

there is some circumstances to fullfill cloud facility.
IaaS------Infrastructure as a Service
PaaS------Plateform as a Service
SaaS------Software as a Service

If any software supports these features then that software is comes under cloud.

What is Grid in oracle....

To understand Grid we need first to understand RAC. RAC is Real application Cluster and cluster defines grouping of server.
Figure


Dtatbase and Oracle Overview



Collection of RAC is called Grid. RAC improves Availability of server. and from 9i database acessed by multiple server that is known as Grid. 





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