ORACLE :- Introduction to Oracle

Welcome guys,
Today's post for Oracle Introduction 

What is Oracle ?

Oracle Database is an object-relational database management system produced and marketed by Oracle Corporation. An Oracle database is a collection of data treated as a unit. The purpose of a database is to store and retrieve related information. A database server is the key to solving the problems of information management. In general, a server reliably manages a large amount of data in a multi user environment ,so that many users can concurrently access the same data. The database has logical structures and physical structures. Because the physical and logical structures are separate, the physical storage of data can be managed without affecting the access to logical storage structures.

History 

In 1977, Larry Ellison, Bob Miner, and Ed Oates started the consultancy Software Development Laboratories, which became Relational Software. In 1983, RSI became Oracle Systems Corporation and then later Oracle Corporation.

Oracle Contents  :-  There are different contents -

                         

•  Grid Architecture.            

•  Application Architecture.

•  physical Database Structures.

•  Logical Database structures.

•  Accessing the Database.

Grid Architecture :- 

Compared to other models of computing, IT systems designed and implemented in the grid style deliver higher quality of service, lower cost, and greater flexibility. Higher quality of service results from having no single point of failure, a robust security infrastructure, and centralized, policy-driven management.

Application Architecture :-

Three are two common ways to architect a database.

Client/Server :-

Multiprocessing uses more than one processor for a set of related jobs. Distributed processing reduces the load on a single processor by allowing different processors to concentrate on a subset of related tasks, thus improving the performance and capabilities of the system as a whole.

An Oracle database system can easily take advantage of distributed processing by using its client/server architecture. In this architecture, the database system is divided into two parts: a front-end or a client, and a back-end or a server.

The Client :-

The client is a database application that initiates a request for an operation to be performed on the database server. It requests, processes, and presents data managed by the server. The client workstation can be optimized for its job. For example, it might not need large disk capacity, or it might benefit from graphic capabilities.

Often, the client runs on a different computer than the database server, generally on a PC. Many clients can simultaneously run against one server.

The Server :-

The server runs Oracle software and handles the functions required for concurrent, shared data access. The server receives and processes the SQL and PL/SQL statements that originate from client applications. The computer that manages the server can be optimized for its duties. For example, it can have large disk capacity and fast processors.

Physical Database Structures :-

The physical database structures of an Oracle database, including data files, redo log files, and control files.

       Data in a data file is read, as needed, during normal database operation and stored in the memory cache of Oracle. For example, assume that a user wants to access some data in a table of a database. If the requested information is not already in the memory cache for the database, then it is read from the appropriate data files and stored in memory.

Logical Database Structures :-

A database is divided into logical storage units called table spaces, which group related logical structures together. For example, table spaces commonly group together all application objects to simplify some administrative operations.

Each database is logically divided into one or more table spaces. One or more data files are explicitly created for each table space to physically store the data of all logical structures in a table space. The combined size of the data files in a table space is the total storage capacity of the table space.

 Accessing the Database :-

This section describes Oracle Net Services, as well as how to start up the database.

Network Connections :-

Oracle Net Services is Oracle's mechanism for interfacing with the communication protocols used by the networks that facilitate distributed processing and distributed databases.

Communication protocols define the way that data is transmitted and received on a network. Oracle Net Services supports communications on all major network protocols, including TCP/IP, HTTP, FTP, and WebDAV.