How to add constraints in Navicat

How to add constraints in Navicat? Adding constraints in Navicat includes the following steps: Select the table Open table design view Add constraints (primary key, foreign key, unique, non-null, default value) Configure constraints Save changes

How to add constraints in Navicat

Adding constraints in Navicat is a basic database management task that can help ensure the integrity and accuracy of data sex. Here is a step-by-step guide to adding constraints:

Step 1: Select the table

Open the database table to which you want to add constraints in Navicat.

Step 2: Open Table Design View

Right-click on the table name and select "Design View". This will open the structure view of the table.

Step 3: Add constraints

In Design View, find the Constraints tab. In this tab, you can add the following types of constraints:

• Primary Key: Ensures that each record of the table has a unique identifier.
• Foreign key: Link a table with a column in another table to establish a relationship.
• Unique: Prevent duplicate values ​​in the table.
• Non-null: Requires the column to be non-null.
• Default value: Set a default value for the column if no value is specified when inserting a record.

Step 4: Configure Constraints

For each constraint type, you need to configure specific settings. For example, for a primary key, you need to specify the primary key column; for a foreign key, you need to specify the referenced table and column.

Step 5: Save changes

After entering all the necessary information, click the Save button to save the constraints.

Example:

To add a primary key constraint to the Customer Number column in the Customers table, follow these steps:

1. Open the "Customer" table.
2. Open "Design View".
3. In the Constraints tab, click Add Primary Key.
4. Select "Customer Number" from the field list.
5. Click "OK".

After completing these steps, the "Customer Number" column will become the primary key, ensuring that each customer in the table has a unique identifier.

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