SQL

SQL Primary Key Error

-- NOT NULL Constraint Error
-- The value of the primary key is NULL
INSERT INTO Colleges(college_id, college_code, college_name)
VALUES ("ARD12", "Star Public School");

-- Insertion Success
INSERT INTO Colleges(college_id, college_code, college_name)
VALUES (1, "ARD12", "Star Public School");

-- UNIQUE Constraint Error
-- The value of college_id is not unique
INSERT INTO Colleges(college_id, college_code, college_name)
VALUES (1, "ARD12", "Star Public School");