如何使用python3将值插入到sql表中？

Question

I'm trying to setup a MQTT client using the Paho library. With that there are no problems, but I'm trying to insert the received publishes in a sql database. I'm converting the received payload string into a dictionary and add a few entries. When executing the following code:

def insert_values(db_connection=None, topic=None, payload=None, time_received=None):
    query_1 = "SELECT topic_id FROM topics WHERE topic = %s"
    query_2 = """INSERT INTO measurements (start_time, end_time, value, max_value, min_value, time_received, topic_id)
                 VALUES (%(start_time)s, %(end_time)s, %(value)s, %(max_value)s, %(min_value)s, %(time_received)s, 
                        %(topic_id)s)"""
    cursor = db_connection.cursor(prepared=True)
    topic_id = cursor.execute(query_1, topic)
    payload["time_received"] = time_received
    payload["topic_id"] = topic_id
    cursor.executemany(query_2, payload)
    db_connection.commit()
    db_disconnect(db_connection, cursor)

I get the following error:

Caught exception in on_message: 1210: Incorrect number of arguments executing prepared statement

The payload looks like this:

payload = {
        "Starttime:": 2020-02-18 10:11:22.2145563,
        "Endtime:": 2020-02-18 10:12:22.2145563,
        "Average Humidity:": 44.256241,
        "Number of Values:": 22,
        "Max Humidity:": 44.586214,
        "Min Humidity:": 44.012148521)
}

Plus some additional info, like the time the payload was received. In the insert_values method I'm trying to get the topic_id from the table topics and write it into the payload.

Edit: The table in which the measurements are to be written looks like this:

CREATE TABLE IF NOT EXISTS measurements
(measurement_id INT AUTO_INCREMENT,
 start_time DATETIME,
 end_time DATETIME,
 value FLOAT,
 max_value FLOAT,
 min_value FLOAT,
 time_received DATETIME,
 topic_id INT,
 PRIMARY KEY (measurement_id),
 FOREIGN KEY (topic_id) REFERENCES topics(topic_id))

Answer 1

Your payload has 6 keys, and then you add another 2 that makes it 8 In your query you have only 7 arguments I'm not sure but i think you forgot to add "Average Humidity" EDIT : After seeing your table DESC

    query_2 = """INSERT INTO measurements (start_time, end_time, value, max_value, min_value, time_received, topic_id)
             VALUES (%s,%s,%s,%s,%s,%s,%s)"""
cursor = db_connection.cursor(prepared=True)
topic_id = cursor.execute(query_1, topic)
payload["time_received"] = time_received
payload["topic_id"] = topic_id
payload.pop("Average Humidity:", None)
cursor.executemany(query_2, payload)
db_connection.commit()
db_disconnect(db_connection, cursor)

Answer 2

Here:

"""VALUES (%(start_time)s, %(end_time)s, %(value)s, %(max_value)s, %(min_value)s, %(time_received)s, %(topic_id)s)"""

and here:

payload = {
    "Starttime:": 2020-02-18 10:11:22.2145563,
    "Endtime:": 2020-02-18 10:12:22.2145563,
    "Average Humidity:": 44.256241,
    "Number of Values:": 22,
    "Max Humidity:": 44.586214,
    "Min Humidity:": 44.012148521)
}

Your payload keys must match the query's placeholders names - or your placeholders match the payload keys. Your db client will definitly not try and guess that "start_time" and "Starttime" are actually supposed to be the same thing. And you of course must have mathcing keys for all the query's placeholders.