. Oracle Database is developed by Oracle Corporation which is one of the most popular databases used nowadays for various applications.
      . It is available in different versions like Oracle 10g, Oracle 11g, Oracle 12 c.
      . When we download Oracle database, it provides database and Client program called "Run SQL Command Line" to write queries for the database.
      . Download Oracle database from internet.

    . Click on Accept Agreement and download setup file which is related to OS of computer.

    . After downlading, unzip the folder and open setup file and install it.

  . It opens installation setup. Click on Next.

   . Accept the license agreement and click on Next.

   . Select the destination folder and click on Next.

   . Give a password for the database account SYSTEM.

   . Finally click on Install.

   . Now open the SQL command prompt.

   It opens a SQL Command window as follows:

    . Enter connect followed by user-name and password which we set during installation.

 Creating a Table:

    Table can be created using the following syntax:
       CREATE TABLE table_name (Column_1 datatype, Column_1 datatype, Column_1 datatype);

 Inserting data into tables:

   . Data can be inserted into the tables using the following syntax:
     INSERT INTO table_name VALUES(List of values separated by commas);

Reading data from table:

   . We use the following command to read data from table:
      SELECT * FROM table_name;
   . To read specific column data from a table, we can use the following syntax:
      SELECT column1, column2 FROM table_name;

 Updating data in a table:

  . We use the following command to update the record in table:
    UPDATE table_name SET Column_name=new_value WHERE condition

Using Constraints using ALTER command:

   . Alter command can be used in many ways.
   . We can add, delete, change datatype of a column and also we can add a constraint to the column.
   . Below command shows how to add a constraint using Alter command.
     ALTER TABLE table_name ADD CONSTRAINT constraint_name PRIMARY KEY(Column_name);

   . After adding a primary key, try to insert a row with duplicate data, it shows error.

Filtering Data:

   . Filtering data means it displays the data as mentioned in the condition written after WHERE.

Deleting a record:

  . Following command is used to delete a record from a table:
    DELETE FROM table_name WHERE condition


  . Rollback command is used to undo the previous action.


   . It is used to save the last action permanently.
   . After committing, data cannot be restored back.