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Aaron Banerjee
6,876 Pointspython database integrity question
Hi everyone. I am relearning python databases and had some questions about how they work, more importantly, the integrity error associated with them which we learned in one of the videos.
def add_students():
for student in students:
try:
Student.create(username=student['username'],points = student['points'])
except IntegrityError:
student_record = Student.get(username=student['username'])
student_record.points=student['points']
student_record.save()
db.connect()
db.create_tables([Student],safe=True)
add_students()
print("Our top student right now is: {0.username}".format(top_student()))
do we use the try and except above in add_students in order to check if a username already exists in the database. so that we should therefore just change the points?
2 Answers
Alex Koumparos
Python Development Techdegree Student 36,887 PointsHi Aaron,
Yes, you are exactly right. The IntegrityError is triggered if creating a record violates the unique constraint set on the student's name (i.e., there can only be one student record with a particular name). We can deduce from the violation of the unique constraint that there must already exist a student with that name, and so we can update their existing record instead of replacing it with a new one.
Cheers
Alex
Aaron Banerjee
6,876 Pointson all databases, do we need a function like this in order to stop integrity errors?