How to set unique constraints in navicat

The steps to set unique constraints through Navicat are as follows: Select the table to which you want to add the constraint. Go to the Design tab, click Add Constraint, and select Unique. Check the fields to be included in the constraint. Specify the constraint name (optional). Click OK and save the table to apply the changes. Unique constraints ensure field uniqueness, but cannot be applied to null fields and are different from primary key constraints.

How to set unique constraints in Navicat

Navicat is a popular database management tool that allows users Easily set table constraints. One important type of constraint is the unique constraint, which ensures the uniqueness of a field in a table. Here's how to set a unique constraint in Navicat:

Step 1: Select the table

• Open the target database in Navicat.
• In the navigation panel on the left, expand Database and select the table to which you want to add constraints.

Step 2: Add Constraints

• Select the table and go to the Design tab.
• In the "Constraints" section, click the "Add Constraint" button.
• Select "Unique" from the drop-down menu.

Step 3: Select fields

• In the "Fields" section, check the fields you want to include in the unique constraint.
• These fields must be unique, otherwise the insertion will fail.

Step 4: Specify a constraint name (optional)

• In the Name field, enter a name for the unique constraint.
• This name is used to refer to the constraint and help identify its purpose.

Step 5: Save changes

• Click the "OK" button to add the constraints to the table.
• Save the table to apply changes.

Restrictions and Notes:

• Unique constraints cannot be applied to null fields.
• Attempts to insert duplicate values ​​will result in an error and abort the query.
• Unique constraints are different from primary key constraints. A primary key constraint also enforces field uniqueness, but it also has other uses, such as identifying each record of a table.

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