PostgreSQL Insert Record: Insert one row into a table to ensure that no duplicate values will be entered in the key column

7. Write a SQL statement to insert one row in the jobs table to ensure that no duplicate values will be entered into the job_id column.

Sample Solution:

Code:

Here is the code to create a sample table jobs:

CREATE TABLE jobs ( 
JOB_ID integer NOT NULL UNIQUE , 
JOB_TITLE varchar(35) NOT NULL, 
MIN_SALARY decimal(6,0)
);

Now insert a row into the table jobs :

INSERT INTO jobs VALUES(1001,'OFFICER',8000);

Here is the command to see the list of inserting rows :

postgres=# SELECT * FROM jobs;
 job_id | job_title | min_salary
--------+-----------+------------
   1001 | OFFICER   |       8000
(1 row)

Now, try to insert the duplicate value in the key column and see what happen :

postgres=# INSERT INTO jobs VALUES(1001,'OFFICER',8000);
ERROR:  duplicate key value violates unique constraint "jobs_job_id_key"
DETAIL:  Key (job_id)=(1001) already exists.

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