NOT NULL constraint failed: Time.start peewee

Question

I’m trying to create a tables in Flask app.
For creating DB I use peewee library.

When run func, I receive an error: NOT NULL constraint failed: Time.start

Can some one explain how to insert data in to database correctly

models.py

from peewee import *


db = SqliteDatabase('report.db')


class MainModel(Model):
    id = PrimaryKeyField(null=False)

    class Meta:
        order_by = 'id'
        database = db

class Drivers(MainModel):

    code = CharField()
    name = CharField()

    class Meta:
        db_table = 'Drivers'


class Time(MainModel):

    name = ForeignKeyField(Drivers)
    start = IntegerField()

    class Meta:
        db_table = 'Time'

My script for insert data to database:

from reports.report import parse_racer_team, build_report, read_file, parse_time_lap
from models import Drivers, Time , db


DATA = 'data/'


def incert_drivers_data(path):
    drivers = parse_racer_team(path)
    start = read_file(path + 'start.log')
    end = read_file(path + 'end.log')
    for item in drivers.items():
        Drivers(
            code=item[0],
            name=item[1]
        ).save()
    for name in Drivers.select():
        Time(
            name=name.name
        ).save()
    for time in start:
        Time(
            start=time
        ).save()


Drivers.create_table()
Time.create_table()
incert_drivers_data(DATA)

content of start.log is :
[(‘SVF’, ‘2018-05-24 12:02:58.917’), (‘NHR’, ‘2018-05-24 12:02:49.914’), (‘FAM’, ‘2018-05-24 12:13:04.512’), (‘KRF’, ‘2018-05-24 12:03:01.250’)]

Please help me understand my mistakes.

Asked By: DmitryTok

||

Source

Answer 1

You just need to add null=True to start field in Time model. The issue gets triggered when an action tries to set None as a value to a field while it is not explicitly allowed.

Answered By: nouraellm

Answer 2

The solution turned out to be to combine all the data that is needed into one dictionary with one key and value in the form of a list
As a result, through the loop it turned out to push the data into the desired columns the first time.
peewee, apparently, is picky about models, since you need to enter all the fields into the model at once. If you do it separately, then the data will not be entered (There will be an error peewee.IntegrityError: NOT NULL constraint failed)
As the problem was solved, it turned out that data is not created through save() (as it was written in the documentation). All work with the creation of new objects goes through create(). Then there was a debriefing with a connected field ForeignKeyField, for a long time I could not figure out how to put the already received id into a connected field of another model. As a result, the code from the same documentation helped

models.py

from peewee import *


db = SqliteDatabase('report.db')


class MainModel(Model):
    id = PrimaryKeyField(null=False)

    class Meta:
        order_by = 'id'
        database = db

class Drivers(MainModel):

    code = CharField()
    name = CharField()

    class Meta:
        db_table = 'Drivers'


class Time(MainModel):

    code = ForeignKeyField(Drivers)
    start = DateTimeField()
    end = DateTimeField()

    class Meta:
        db_table = 'Time'

utils.py

from reports.report import parse_racer_team, build_report, read_file, parse_time_lap
from models import Drivers, Time , db


DATA = 'data/'

def incert_data(path):
    start = read_file(path + 'start.log')
    end = read_file(path + 'end.log')
    racers = parse_racer_team(path)
    all_data = {}
    for key, value in start:
        all_data[key] = [value]
    for key, value in end:
        all_data[key].append(value)
    for key, value in racers.items():
        all_data[key].append(value)
    for key, value in all_data.items():
        code_id = Drivers.create(code=key, name=value[2])
        Time.create(
            code=code_id,
            start=value[0],
            end=value[1]
        )

if __name__ == '__main__':
    db.create_tables([Drivers, Time])
    incert_data(DATA)

Answered By: DmitryTok

NOT NULL constraint failed: Time.start peewee

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