What is Database?
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- A Database is a organized collection of interrelated data.
- For e.g. A university database stores data related to students,course, faculty etc.. which is interrelated.
- In Database we organise data using tables.
- We use DB to store Data.


What are the types of databases?
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- Databases are two types:
  1]OLTP Database (Online transaction processing)
  2]OLAP Database (Online analytical processing)
- OLTP is used to store day-to-day transactions.
- OLAP is used to analyze already stored data.
- framework technologies like - hadoop , spark & scala , data science.
- This technologies are mainly used for data analysis.It comes under OLAP.
- OLTP is for running business and OLAP is to analyze business.
- OLTP stores current data whereas OLAP stores historical data.

What are the day-to-day operations on Database?
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- C create
- R read
- U update
- D delete
- User can not directly work with database, it requires a software called DBMS.
- Database is storage , DBMS is database management system which is software used to create and to manage database.
- DBMS is an interface between user and database.
- If user wants to perform any operation, they pass instruction to DBMS then DBMS performs the task and gives us output.


Evolution of DBMS :
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- In 1960 companies uses FMS (file management system).
- In 1970 companies uses HDBMS (Hieratchical DBMS) & NDBMS(Network DBMS).
- In 1980 companies uses RDBMS (Relational DBMS).
- In 1990 companies uses ORDBMS (Object Relational DBMS).


Types of DBMS :
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{1 HDBMS
2 NDBMS} - outdated
3 RDBMS
4 ORDBMS


RDBMS:
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- RDBMS concepts introduced by E.F.CODD
- He introduced 12 rules called codd rules.
- A DB software that supports all 12 rules is called perfect rdbms software.
- According to E.F.CODD in RDBMS data must be organized in tables i.e. rows and columns.
- In RDBMS data is stored in rows and columns.
- Vertical collection of cells are called columns,fields or attributes.
- Horizontal collection of cells are called rows, record or tuple.
- row contains field values.
- Database is collection of tables.
- Table is collection of rows & columns.
- Row is collection of field values.
- Column is collection of values assigned to one field.


E.F.CODD says:-
- Every table must contains primary key to uniquely identify the records.
- ex :- Bank acc. no. , Company emp. ID , for citizen of india Aadhar no., for every class roll no. this are all primary key to identify each person.


RDBMS softwares:-
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Oracle.
MySQL.
SQL Server.
PostgreSQL.
IBM DB2.
Microsoft Access.
SQLite.
MariaDB.
LibreOffice Base.


What is SQL Server?
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- SQL server is a RDBMS product from microsoft used to create and to manage database.
- It also supports few concepts of ORDBMS.


ORDBMS :-
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- Object Relational DBMS.
- It is the combination of RDBMS & OOPS.
      
	 ORDBMS = RDBMS + OOPS (reusability)

	Data abstraction,
	Data encapsulation,
	Data inheritance,
	Data polimorphism are OOPS concepts.

- RDBMS doesn't support reusability but ORDBMS supports reusability.

ORDBMS softwares:-
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ORACLE
SQL server
POSTGRESQL