1.) What is oracle?
 -    Oracle is a powerful relational database software developed by "Larry Ellison" & his friend "Bob Miner" & "ED Oat" in the year 1977 at software development lab (SDL)

History of Oracle Databse
a.) 1979 RSI (Relational Software Insi) developed oracle V2 just support SQL.
b.) 1982 change name "Oracle Corporation".
c.) 1983 Oracle V3 developed in C.
d.) 1984 V4.
e.) 1985 V5.
f.) 1988 V6 (PL/SQL)
g.) 1990 V8
h.) 1999 Oracle 8i
i.) 2001 Oracle 9i
j.) 2003 Oracle 10g
k.) 2007 Oracle 11g
l.) 2013 Oracle 12c
m.) 2018 Oracle 18c
n.) 2019 Oracle 19c

2.) What is Databse?
-      Organized collection of data in a particular format, so that it can be easily accessed and managed. It also store data in a secure manner.

    Advantages of database:
a.) Data retrival
b.) Security
c.) Data redundency
d.) Data Integrity 
e.) Indexing

       Object of Oracle Databse:
       a.) Table: It is used to store information.
       b.) View: Logically represent subset of data from one or more table or view.
       c.) Squence: Used to generate primary key values.
       d.) Index: It is used to improve the performance of query.
       e.) Synonym: Used to gives alternate name to object.

3.) Datatypes in Oracle?
 -    Datatype defines type of info & the amount of spaces required for a particular column.

4.) Rules to create a table:
   a.) The name of table must be unique in orcale database.
   b.) The maximum length of table is 30 characters long.
   c.) A table contain maximum 100 columns and unlimited record.
   d.) The attribute name of table must be unique.
   e.) The name of table can be define by the help of alphabet it could be in uppercase or lower case, digits & 3 - special symbols (-,#,$).

a.) How to install oracle?


b.) How to create a table in oracle?
-   Syntax: create table <table_name> (var_name <datatype>, var_name <datatype>);
-    Ex    : create table student(roll number(5), name char(30));
5.) What is SQL? → SQL stand for Structural Query Languages. Every relational database software intract with a language known as SQL, because It's a simple english like language which guidelines are provided by a standard organisation 'ANSI' adopted by all database vendors like Oracle, Mysql, Microsoft, etc... An SQL is very complex language to reduce its complexity, it can sub-categorized into 5 - sub languages. 1.) DDL (Data Definition Language): → It has 5 commands which are CREATE, DROP, TRUNCATE, ALTER, RENAME. 2.) DML (Data Manipuation Language): → It has 3 commands which are INSERT, UPDATE, DELETE. 3.) DQL (Data Query Language): → It has 1 command which is SELECT. 4.) DCL (Data Control Language): → It has 2 commands which are GRANT, REVOKE. 5.) TCL (Transaction Control Language): → It has 4 commands which are COMMIT, ROLLBACK, SAVE, POINT. 6.) SQL Sub-languages:-
a.) DDL (Data Definition Language): → This Sub-language deals with objects of databse like, table, view, sequence, etc. It provides 5 - command:- 1.) CREATE 2.) RENAME 3.) ALTER 4.) TRUNCATE 5.) DROP     1.) CREATE: This command is used to create a table.     → Syntax: create table <table_name> (<field1> <datatype>, <field2> <datatype> -------- <field n><dataype>);     → Example: create table Emp(Eid number, Ename varchar(30));          * How to insert data in table?      → insert into Emp values(20, 'Abhijeet');    * How to view inserted data from table?    → select * from Emp;     2.) RENAME: This command is used to rename the table.     → Syntax: rename table-name to new-name;     → Example: rename Emp to Employee;     3.) ALTER: This command is used to add rows, column, etc.     → Syntax: Alter Table table-name Add column-name datatype;
    * How to view the table colume?     → desc <table-name>;
    → Example: alter table Employee add Eadd varchar(30);     4.) TRUNCATE: It is used to remove the records from table.     → Syntax: truncate table <Table-name>;     → Example: truncate table Employee;     5.) DROP: It will remove data as well as table permanently     → Syntax: drop table table-name;     → Example: drop table Employee;     Difference between Truncate & Drop.
     Trincate Drop
    a.) This command is used to a.) It is used to remove both table_records     remove record only. & table permanently.    b.) Syntax: b.) Syntax: drop table <table_name> truncate table <Table-name>; b.) DML (Data Manipuation Language): → It deals with data of objects. It provides 3 - command.     a.) INSERT: This command is used to insert the data in table.     → Syntax: insert into <table_name> values (data1, data2, ------ data n);     → Example: insert into employee(eid, ename, eadd);     b.) UPDATE: This command is used to update data from the table.     → Syntax: update <table_name> set <field>=<update> where <fiels> = <reference_data>;     → Example: update employee set Ename='Abhishek' where Eid=2;
    c.) DELETE: This command is used to delete data from the table.     → Syntax: delete from <table_name>; -- It will delete all records.     → Example: delete from Employee;     → Syntax: delete from <table_name> where condition_statement; -- It will delete particular records.     → Example: delete from Employee where Eid=2;
c.) DQL (Data Query Language): → It is used to retrieve information from dtabase. It has only one select command.     a.) SELECT: This command is used to select the table to view records.     → Syntax: select * from <table_name>; -- It wil show all records of table.     → Example: select * from Employee;     → Syntax: select * from <table_name> where condition_statement; -- It wil show particular records from table row.     → Example: select * from Employee where Eid=3;     → Syntax: select col_name from <table_name>; -- It wil show recorrd of particular column.     → Example: select Ename from Employee;