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Will Foreign Key Allow Null Values?

Chloe Bennett • • 7 min read
Will Foreign Key Allow Null Values?

Short answer: Yes, it can be NULL or duplicate. I want to explain why a foreign key might need to be null or might need to be unique or not unique. First remember a Foreign key simply requires that the value in that field must exist first in a different table (the parent table).

Which key can accept null values?

Primary key will not accept NULL values whereas Unique key can accept NULL values. A table can have only primary key whereas there can be multiple unique key on a table.

How do I set foreign key to null?

The syntax for creating a foreign key with set null on delete using a CREATE TABLE statement in SQL Server (Transact-SQL) is: CREATE TABLE child_table ( column1 datatype [ NULL | NOT NULL ], column2 datatype [ NULL | NOT NULL ], ...

Chloe Bennett
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Chloe Bennett

Chloe Bennett explores the intersection of pop culture, streaming entertainment, digital trends, and contemporary lifestyle. Her weekly commentary reaches thousands of culture enthusiasts.