Microsoft.NET

……………………………………………….Expertise in .NET Technologies

Introduction to ORACLE – Part II

Posted by Ravi Varma Thumati on October 12, 2009

Basic Concepts:

Database:

Every person or an object has some information associated with them. These pieces of data when grouped in an organized way is called database. A database is a collection of programs that are used to maintain and manipulate data.

DataBase Management System (DBMS)

Database management system is the key for solving problems of information management. A DBMS is nothing but software with a rich set of tools which can reliably manage a large amount of data in a multi user environment.

A DBMS must also be secure from unauthorized access. It must give high performance to the users of the database. Must provide efficient results for failure recovery; It must also enforce the business rules that dictate the standards of acceptable data by providing data integrity.

Relational DBMS (RDBMS)

A relational database is nothing but thinking about the data available should be structured and stored. The key to the design of this kind of a database is to understand the relationship within the different pieces of information and the structured information base to reflect those relationships. The key success to a relational database is the structure that should be well defined and which never changes. Only the data that goes into the structure changes in RDBMS.

Data

Pieces of details about any subject of data

Ex:       Name of a person

                        Age

                        Gender

Information

The data that is organized in a meaningful way is information

Ex:       Information about a person

            Name

            Date of Birth

            Age

            Gender

            Height

            Weight

Database

The needed and available information set, collected and kept in a logical way is called database.

Data Organization

Most familiar way of representing data is in tabular form. If is easy to visualize, understand, grasp the meaning of data and use the data effortlessly.

Ex:       Information presented in non-table form

oracle7

The information presented in this way is less readable and hard to manage and maintain.

The same information is presented in a table form is:

oracle8

Terminology

Table:

It is the basic structure in the database. It contains the columns. Table is identified and referred by a name.

Column:

It is the basic unit of data storage. Some times also refereed as field. It is identified and referenced by a unique column name with in a table.

Filed:

In general it is same as the column. It also means the value stored at the intersection of a row and column.

Row:

A set of columns/fields (with values) in a table is called rows. A set of values in the output  of a query.

Oracle

ORACLE is a powerful RDBMS product that provides efficient and effective solutions for major database features. This includes:

  • Large databases and space management control
  • Many concurrent database users
  • High transaction processing performance
  • High availability
  • Controlled availability
  • Industry accepted standards
  • Manageable security
  • Database enforced integrity
  • Client/Server environment
  • Distributed database systems
  • Portability
  • Compatibility
  • Connectivity

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 portion

The client executes the database application that accesses database information and interacts with the user.

A back-end or a server portion

The server executes the ORACLE software and handles the functions required for concurrent, shared data access to ORACLE database.

What is SQL and SQL*Plus

Oracle was the first company to release a product that used the English-based Structured Query Language or SQL. This language allows end users to manipulate information of table (primary database object). To use SQL you need not to require any programming experience. SQL is a standard language common to all relational databases. SQL is database language used for storing and retrieving data from the database. Most Relational Database Management Systems provide extension to SQL to make it easier for application developer.

A table is a primary object of database used to store data. It stores data in form of rows and columns.

SQL*Plus is an Oracle tool (specific program) which accepts SQL commands and PL/SQL blocks and executes them. SQL *Plus enables manipulations of SQL commands and PL/SQL blocks. It also performs additional tasks such as calculations, store and print query results in the form of reports, list column definitions of any table, and access and copy data between SQL databases and sends messages to user and accepts responses from the user. SQL *Plus is a character based interactive tool, that runs in a GUI environment. It is loaded on the client machine.

To communicate with Oracle, SQL supports the following categories of commands:

1. Data Definition Language

Create, Alter, Drop and Truncate

2. Data Manipulation Language

Insert, Update, Delete and Select

3. Transaction Control Language

Commit, Rollback and Savepoint

4. Data Control Language

Grant and Revoke

 

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One Response to “Introduction to ORACLE – Part II”

  1. Aw, this was a really quality post. In theory I’d like to write like this too – taking time and real effort to make a good article… but what can I say… I procrastinate alot and never seem to get something done

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