To add a foreign key constraint on the `dept_no` column in the `EMP` table, referring to the `id` column in the `DEPT` table, you would use the `ALTER TABLE` statement in SQL. Here are the steps:

1. First, ensure that the `DEPT` table has a primary key on the `id` column. If it doesn't, you can add it using the following command:

```sql
ALTER TABLE DEPT
ADD PRIMARY KEY (id);
```

2. Next, add the foreign key constraint to the `EMP` table. The `dept_no` column in the `EMP` table will reference the `id` column in the `DEPT` table. Use the following command:

```sql
ALTER TABLE EMP
ADD FOREIGN KEY (dept_no) REFERENCES DEPT(id);
```

This command adds a foreign key constraint to the `dept_no` column in the `EMP` table, which references the `id` column in the `DEPT` table. If a row in the `EMP` table has a `dept_no` that does not exist in the `DEPT` table's `id` column, the database will return an error and reject the change.

Question

To add a foreign key constraint on the `dept_no` column in the `EMP` table, referring to the `id` column in the `DEPT` table, you would use the `ALTER TABLE` statement in SQL. Here are the steps:

1. First, ensure that the `DEPT` table has a primary key on the `id` column. If it doesn't, you can add it using the following command:

```sql
ALTER TABLE DEPT
ADD PRIMARY KEY (id);
```

2. Next, add the foreign key constraint to the `EMP` table. The `dept_no` column in the `EMP` table will reference the `id` column in the `DEPT` table. Use the following command:

```sql
ALTER TABLE EMP
ADD FOREIGN KEY (dept_no) REFERENCES DEPT(id);
```

This command adds a foreign key constraint to the `dept_no` column in the `EMP` table, which references the `id` column in the `DEPT` table. If a row in the `EMP` table has a `dept_no` that does not exist in the `DEPT` table's `id` column, the database will return an error and reject the change.

Knowee AI · Accepted Answer

To add a foreign key constraint on the `dept_no` column in the `EMP` table, referring to the `id` column in the `DEPT` table, you would use the `ALTER TABLE` statement in SQL. Here are the steps:

1. First, ensure that the `DEPT` table has a primary key on the `id` column. If it doesn't, you can add it using the following command:

```sql
ALTER TABLE DEPT
ADD PRIMARY KEY (id);
```

2. Next, add the foreign key constraint to the `EMP` table. The `dept_no` column in the `EMP` table will reference the `id` column in the `DEPT` table. Use the following command:

```sql
ALTER TABLE EMP
ADD FOREIGN KEY (dept_no) REFERENCES DEPT(id);
```

This command adds a foreign key constraint to the `dept_no` column in the `EMP` table, which references the `id` column in the `DEPT` table. If a row in the `EMP` table has a `dept_no` that does not exist in the `DEPT` table's `id` column, the database will return an error and reject the change.

How would you add a foreign key constraint on the dept_no column in the EMP table, referring to the id column in the DEPT table?

Question

How would you add a foreign key constraint on the `dept_no` column in the `EMP` table, referring to the `id` column in the `DEPT` table?

Solution

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