The oracle is the global leaders in the field of software and provides solutions for every tier of business. It specializes the enterprise software products particularly "Database Management Systems". It was founded in 1977 by the CEO of oracle corporation LARRY ELLISON. Oracle has the third largest software revenue after IBM and Microsoft. The company is well known for its database and provides a number of other products including database development, middle-tier software, enterprise resource planning software (ERP), customer relationship management software (CRM) and supply chain management (SCM) software. The Oracle database is Relational database management system(RDMS).
DATABASE:-
In most simple form, a database is a mechanism for storing the data. This data may be logical like values stored in computer program, or may be physical like a file.
Types Of Database:-
- Hierarchical
- Network
- Relational
Relational Model:-
In it the data is broken into the collection of objects and relations that store the actual data. The database contains many table and the data in it is related with other tables data. The Tables that have related data need not to know where related information is stored physically.
The whole Relational Model concept was first intoduced by E. F. Codd in his article of relational model which can be founded here
Querying the Database:-
RDBMS allows you to manipulate relational tables and their contents and provides a language that allows you to create , modify, remove objects in database as well as add, change and delete data. The language used is "Structured Query Language".
SQL is actually a collection of several different languages each having a particular purpose. It is made up of:
1. DATA DEFINITION LANGUAGE:-
It is used to Create and modify database objects Includes CREATE, ALTER, DROP, RENAME and TRUNCATE.
2. DATA MANIPULATION LANGUAGE:-
It is used to modify the data in the tables in the database. Includes INSERT, UPDATE and DELETE. It also includes the extensions to control the transactions in database includes COMMIT , ROLLBACK and SAVEPOINT.
3. DATA CONTROL LANGUAGE:-
It is used to Configure security to perform database tasks and Manipulate database objects . It includes GRANT and REVOKE.
3. DATA CONTROL LANGUAGE:-
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