SQL query issue in Django

Question

I am trying to find out if a value is present in a column in a MySQL table from my django application. This is what I have done:

cursor = connection.cursor()
cursor.execute('SELECT COUNT(*) FROM model_combination_bank WHERE combination = %s AND validity = 1', [combination])
result = cursor.fetchall
if result != 1:
 self.respond('Sorry. The entry code you entered is not valid. Please try again with a valid code.')
 return()

I know for sure that there is a 1 row in the table that matches the SELECT STATEMENT but the self.respond function runs. Can somebody kindly tell me whats wrong with my code.

Answer 1

You didn't call the method:

result = cursor.fetchall()

However you shouldn't really be using raw SQL here. Use the model layer:

result = ModelCombinationBank.objects.filter(validity=1, combination=combination).count()

assuming your model is called ModelCombinationBank. And if all you need to is to check that the combination exists, use exists() instead of count(), since that is a cheaper query.

Answer 2

Another way to see if a value exists and do something if it does:

try:
 obj = ModelCombinationBank.objects.get(validity=1, combination=combination)
 # do something with obj
except ModelCombinationBank.DoesNotExist:
 # do something if not found