There are three main topics in the Oracle they are as follows:
1. Data.
2. Information.
3. Data Base.
4. DBMS(Data Base Management System).
Explanation:
1. Data: What ever we entered into the computer system is know as DATA.
* Data can also be called as "RAW FACTS".
* Data doesn't gives any meaning.
2. Information: Processed data can be called as INFORMATION.
* Information always gives meaning.
3. Data Base: Collection of information stored at one place written in a pre-determined manner belongs to a particular topic (an organization). So, as far easy retrieval.
4. DBMS(Data Base Management System): It is a soft ware which is present in side the data base which can maintain and mange the data with in the data base.
Role of DBMS:
If user need any information from the data base then he has to contact with DBMS and DBMS go to the data base and take the necessary information from the data base and give it to the user.
RDBMS:
This model was developed by a german scientest "E.F.CORD" in 1970 based on mathematical concept called "Relational Algebra".
* Here Relation can be defined as commonness between various objects.
* Relations are divided into three types. They are as follows:
1. One to One Relation.
2. One to Many/Many to One.
3. Many to Many.
Exmplanation:
1. One to One: In this relation one object has relation with only one another object.
ex:: One employee has only one id card.
One customer has only one account number in a bank.
2. One to Many/ Many to One: In this relation one object has the relation with many other objects.
ex:: One faculty manage many other courses.
3. Many to Many: In this relation many objects has relation with many objects.
*All this relations are called as "Degree of relation" (or) "Cardinality".
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