i) ALTER - ALTER statement is used to add/remove an attribute or to modify the datatype of an existing attribute or to add constraint in attribute.
UPDATE - It is used to make changes in the value(s) of one or more columns of existing records in a table. For example, we may require some changes in address, phone number or spelling of name, etc.
ii) DELETE - DELETE statement is used to delete/remove one or more records from a table.
DROP - We use a DROP statement to remove a database or a table permanently from the system. However, one should be very cautious while using this statement as it cannot be undone.
