ORACLE : Introduction of DATA , DATABSE & DBMS

Welcome guys,

in this post I will tell uh  About ORACLE DATABASE

so,

Well Lets Talk About DATABASE First,

 "Database is nothing but its a organized collection of inter-related data". For Ex. University database stores data related to students,courses,faculty etc , a bank database stores data related to customers,transactions etc.

Now Lets Talk About DATABASE MANAGEMENT SYSTEM,

"Its a software that is introduced in 1970s which is used to Create & Manage Database (by performing operations )".

 So,

DBMS are categorized into following category -

• HDBMS - Hierarchical Database Management System
• NDBMS - Network Database Management System
• RDBMS - Relational Database Management System
• ORDBMS - Object Relational Database Management System
• OODBMS - Object Oriented Database Management System

  well we are working on RDBMS now so,

i) RDBMS :-   

1.Its Introduced by E.F.Codd.

2.Introduced 12 Rules called Codd rules.

3.Interesting thing is that ORACLE supports 98% of Codd rules.

4.Codd rules Contains two part A&B but ORACLE support only 1.  

These are the Rules :-

1. Information Rule

2. Guaranteed Access Rule

3. Systematic Treatment of NULL values

4. Active Online Catalog

5. Comprehensive Data Sub-Language Rule

6. View Updating Rule

7. High-Level Insert,Update and Delete Rule

8. Physical Data Independence

9. Logical Data Independence

10. Integrity Independence

11. Distribution Independence

12. Non-Subversion Rule

so these was the rules ,well i will describe it on another post

now talking about some rules -

1. So according to rule Data must be Organized in tables (i.e Rows and Columns )  -

here,

DB = Collection of Tables

TABLE = Collection of Rows and Columns

ROWS = Set of Field Values

COLUMNS = Data Definition

2. A table must contains a Primary Key or uniquely identify records -

 
In This Table , a table is uniquely identified by a Eno ,

so Eno is Primary Key. 

 3. One table related to Another table by using Foreign Key.

 

here is a table name is Department and here D_id is a Primary key ,

so if u want to create another table related to this table than  this primary key will be a Foreign key.

 

 So this is a primary key.

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