Flash cards
Review the key moves
1/4
Core idea
What is the main idea behind SQL NOT NULL Keyword?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
1Quick choice
Which statement best captures the main point of this lesson?
2Fill blank
Complete the missing token from the example code.
___ TABLE Persons (3Order
Put the learning moves in the order that makes the concept easiest to apply.
The following SQL creates a NOT NULL constraint on the "Age" column when the "Persons" table is already created:
The following SQL ensures that the "ID", "LastName", and "FirstName" columns will NOT accept NULL values:
The NOT NULL constraint enforces a column to not accept NULL values, which means that you cannot insert or update a record without adding a value to this field.
Not Null
The NOT NULL constraint enforces a column to not accept NULL values, which means that you cannot insert or update a record without adding a value to this field.
The following SQL ensures that the "ID", "LastName", and "FirstName" columns will NOT accept NULL values:
Example
CREATE TABLE Persons (
ID int NOT NULL,
LastName varchar(255) NOT NULL,
FirstName varchar(255)
NOT NULL,
Age int
);The following SQL creates a NOT NULL constraint on the "Age" column when the "Persons" table is already created:
ALTER TABLE Persons
MODIFY Age int NOT NULL;