How to: Delete Foreign Key Relationships (Visual Database Tools)
Delete a foreign key constraint when you want to remove the requirement to enforce referential integrity.
To delete a foreign key constraint
In Object Explorer, right-click the table with the constraint, and click Design.
The table opens in Table Designer.
From the Table Designer menu, click Relationships.
In the Foreign Key Relationships dialog box, select the relationship in the Selected Relationship list.
Click the Delete button.
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