MIS Exam 1 Review Video: SQL and 10-step tutorial

What does DDL stand for?

Data Definition Language

What does DML stand for?

Data Manipulation Language

What is the purpose of DDL commands?

To define or modify the structure of a database.

What are the main DDL commands?

CREATE TABLE, ALTER TABLE, DROP TABLE.

What is the purpose of DML commands?

To manipulate data inside tables.

What are the main DML commands?

1. insert into … values

2. delete from … where

3. select * from … where

4. update … set … where

hat is the difference between INSERT TABLE and INSERT INTO?

Insert table is incorrect since table is for ddl not dml

What does the WHERE clause do in SQL?

Filters which records are affected by a statement.

Why is the WHERE clause important?

Without it, updates or deletes affect every record — irreversible error.

Example: UPDATE Employee SET LastName = 'Patel'; — what’s wrong?

Missing where clause

What happens if you forget the WHERE clause?

You change every record; there is no undo.