Python dict进入MySQL executemany

Question

My statement should match syntax, but I get error "Not all parameters were used in the SQL statement") mysql.connector.errors.ProgrammingError: Not all parameters were used in the SQL statement

stmt = "UPDATE abbcards SET carPlate = '%(values)s' WHERE carId =%(id)s"
params = [tuple(cusSurname.values()), tuple(cusSurname.keys())]
cur.executemany(stmt, params)

What's wrong? I've defined the operation and seq_params variables.

Answer 1

@ThePjot is somewhat right in their comment. You are using named placeholders in your query string ( %(values)s and %(id)s ), so you have to pass the parameters in the form of a dict.

BUT , you also call executemany which needs a list or tuple of parameters . Many times, executemany does nothing else than calling execute multiple times while iterating over params , passing an element of parameters in every iteration. That means, each element of params must contain a full set of parameters for the query.

Looking at your query string you need two parameters to be substituted.

stmt = "UPDATE abbcards SET carPlate = '%(values)s' WHERE carId =%(id)s"
# Side note: the quote chars around %(values)s are quite certainly wrong here

From your code examples, one could assume that cusSurname is a dict. Let's say it looks like this:

cusSurname = {'1': 'a1b1c1',
              '2': 'a2b2c2',
              '3': 'a3b3c3'}

What you are doing in the code above, is passing all the keys and all the values of cusSurname to executemany .

params = [('a1b1c1', 'a2b2c2', 'a3b3c3'), ('1', '2', '3')]

This would lead to a final query string of:

UPDATE abbcards SET carPlate = '\'a1b1c1\'' WHERE carId ='a2b2c2'

... with one element from the first parameter tuple not being substituted, which leads to mysql.connector.errors.ProgrammingError: Not all parameters were used in the SQL statement , before the second statement could be formed from the string and the params, which would look like:

UPDATE abbcards SET carPlate = '\'1\'' WHERE carId ='2'

... and raise the same exception. What you'll want to do, is end up with a list/tuple of dicts consisting of individual items of your cusSurname :

stmt = "UPDATE abbcards SET carPlate = %(values)s WHERE carId =%(id)s"
params = [dict({'id': k, 'values': v}) for k,v in cusSurname.items()]
# [{'id': '1', 'values': 'a1b1c1'}, {'id': '2', 'values': 'a2b2c2'}, {'id': '3', 'values': 'a3b3c3'}]
cur.executemany(stmt, params)

Or switch to positional params:

stmt = "UPDATE abbcards SET carPlate = %s WHERE carId =%s"
params = [tuple(i) for i in cusSurname.items()]
# [('1', 'a1b1c1'), ('2', 'a2b2c2'), ('3', 'a3b3c3')]
cur.executemany(stmt, params)