Differentiate between the following statements:
ALTER and UPDATE
ALTER TABLE statement is used to make changes in the structure of a table like adding, removing or changing datatype of column(s). On the other hand, UPDATE statement is used to modify existing data in a table. Thus, ALTER works on the table structure while UPDATE works on the data stored in the table.
DELETE and DROP
DELETE is a DML statement used to remove records from a table. DROP is used to remove database objects like tables entirely. DELETE removes data but keeps the table structure intact, while DROP removes the complete table including its structure and data.
Explanation
The textbook context clearly defines ALTER TABLE as a statement for structural changes (adding/removing/changing columns) and UPDATE as a statement for modifying existing data. DELETE is mentioned as part of DML. For DROP, while not explicitly defined in the provided context, it is a standard SQL concept taught alongside DELETE to show the difference between removing data versus removing objects.