How to use the peewee.PrimaryKeyField function in peewee

fsequenceid = IntegerField(column_name='fSequenceID')
    fstarttime = DateTimeField(column_name='fStartTime', null=True)
    fstoptime = DateTimeField(column_name='fStopTime', null=True)

    class Meta:
        table_name = 'FillStarStatus'
        indexes = (
            (('fnight', 'fsequenceid'), True),
        )
        primary_key = CompositeKey('fnight', 'fsequenceid')


class MeasurementType(FactDataModel):
    fisunlimited = IntegerField(column_name='fIsUnlimited')
    fmeasurementtype = CharField(column_name='fMeasurementType')
    fmeasurementtypekey = PrimaryKeyField(column_name='fMeasurementTypeKey')
    fmeasurementtypename = CharField(column_name='fMeasurementTypeName', unique=True)
    fneedssource = IntegerField(column_name='fNeedsSource')

    class Meta:
        table_name = 'MeasurementType'


class ObservationTimes(FactDataModel):
    fmjd = IntegerField(column_name='fMjd')
    fmoonrise = DateTimeField(column_name='fMoonRise')
    fmoonset = DateTimeField(column_name='fMoonSet')
    fnight = PrimaryKeyField(column_name='fNight')
    fnumdarkhours = FloatField(column_name='fNumDarkHours')
    fstartdarknight = DateTimeField(column_name='fStartDarkNight')
    fstartdarktime = DateTimeField(column_name='fStartDarkTime')
    fstartobservation = DateTimeField(column_name='fStartObservation')

mid = pw.PrimaryKeyField()
        content = pw.TextField(null=True)
        mlink = pw.CharField(max_length=255, null=True)
        mtype = pw.IntegerField(null=True)
        posted = pw.DateTimeField(null=True)
        read = pw.DateTimeField(null=True)
        receivedby = pw.ForeignKeyField(backref='message_set', column_name='receivedby', field='uid', model=migrator.orm['user'], null=True)
        sentby = pw.ForeignKeyField(backref='user_sentby_set', column_name='sentby', field='uid', model=migrator.orm['user'], null=True)
        subject = pw.CharField(max_length=255, null=True)

        class Meta:
            table_name = "message"

    @migrator.create_model
    class SiteLog(pw.Model):
        lid = pw.PrimaryKeyField()
        action = pw.IntegerField(null=True)
        desc = pw.CharField(max_length=255, null=True)
        link = pw.CharField(max_length=255, null=True)
        time = pw.DateTimeField()
        uid = pw.ForeignKeyField(backref='sitelog_set', column_name='uid', field='uid', model=migrator.orm['user'], null=True)
        target = pw.ForeignKeyField(backref='sitelog_set', column_name='target_uid', field='uid', model=migrator.orm['user'], null=True)

        class Meta:
            table_name = "site_log"

    @migrator.create_model
    class SiteMetadata(pw.Model):
        xid = pw.PrimaryKeyField()
        key = pw.CharField(max_length=255, null=True)
        value = pw.CharField(max_length=255, null=True)

db_table = 'collection'


class SampleSet(MySQLModel):
    sample_set  = PrimaryKeyField(db_column='sample_set_pk')
    dataset     = ForeignKeyField(Dataset, db_column='dataset_pk', to_field='dataset', related_name='sample_sets')
    collection  = ForeignKeyField(Collection, db_column='collection_pk', to_field='collection', related_name='sample_sets')
    sample_size = IntegerField()
    phenotype   = CharField(null=True)

    class Meta:
        db_table = 'sample_set'


class DatasetFile(MySQLModel):
    dataset_file    = PrimaryKeyField(db_column='dataset_file_pk')
    dataset_version = ForeignKeyField(DatasetVersion, db_column='dataset_version_pk', to_field='dataset_version', related_name='files')
    name            = CharField()
    uri             = CharField()
    bytes           = IntegerField()

    class Meta:
        db_table = 'dataset_file'


class UserAccessLog(MySQLModel):
    user_access_log = PrimaryKeyField(db_column='user_access_log_pk')
    user            = ForeignKeyField(User, db_column='user_pk', to_field='user', related_name='access_logs')
    dataset         = ForeignKeyField(Dataset, db_column='dataset_pk', to_field='dataset', related_name='access_logs')
    action          = EnumField(null=True, values=['access_requested','access_granted','access_revoked','private_link'])
    ts              = DateTimeField()

import datetime

import peewee

from windseed.settings import db


class Model(peewee.Model):
    """
    Common db model:
        uid - primary key
        uts - timestamp (auto on creation)
    """
    uid = peewee.PrimaryKeyField(unique=True, index=True)
    uts = peewee.DateTimeField(default=datetime.datetime.now, index=True)

    class Meta:
        database = db.pool
        order_by = ('-uts', )

dataset           = ForeignKeyField(Dataset, db_column='dataset_pk', to_field='dataset', related_name='versions')
    version           = CharField()
    description       = TextField()
    terms             = TextField()
    var_call_ref      = CharField(null=True)
    available_from    = DateTimeField()
    ref_doi           = CharField(null=True)
    data_contact_name = CharField(null=True)
    data_contact_link = CharField(null=True)

    class Meta:
        db_table = 'dataset_version'


class Collection(MySQLModel):
    collection = PrimaryKeyField(db_column = 'collection_pk')
    name       = CharField(null = True)
    ethnicity  = CharField(null = True)

    class Meta:
        db_table = 'collection'


class SampleSet(MySQLModel):
    sample_set  = PrimaryKeyField(db_column='sample_set_pk')
    dataset     = ForeignKeyField(Dataset, db_column='dataset_pk', to_field='dataset', related_name='sample_sets')
    collection  = ForeignKeyField(Collection, db_column='collection_pk', to_field='collection', related_name='sample_sets')
    sample_size = IntegerField()
    phenotype   = CharField(null=True)

    class Meta:
        db_table = 'sample_set'

def gen_field(self, field):
        """ Function description. """
        if isinstance(field.scheme, AutoField)\
                and self.__mixer and self.__mixer.params.get('commit'):
            return field.name, SKIP_VALUE
        return super(TypeMixer, self).gen_field(field)

import eventlet
import logging
logging.basicConfig(level=logging.WARN)
logger = logging.getLogger('data_server')
eventlet.monkey_patch()

############################################################
#
# Database
#
############################################################
db = peewee.SqliteDatabase('data_server.db')


class Memory(peewee.Model):
    id = peewee.PrimaryKeyField()
    data = peewee.BlobField()
    generation = peewee.IntegerField()
    date = peewee.DateTimeField(default=datetime.datetime.now)

    class Meta:
        database = db


class Weights(peewee.Model):
    id = peewee.PrimaryKeyField()
    data = peewee.BlobField()
    generation = peewee.IntegerField()
    date = peewee.DateTimeField(default=datetime.datetime.now)

    class Meta:
        database = db

db_table = 'dataset_file'


class UserAccessLog(MySQLModel):
    user_access_log = PrimaryKeyField(db_column='user_access_log_pk')
    user            = ForeignKeyField(User, db_column='user_pk', to_field='user', related_name='access_logs')
    dataset         = ForeignKeyField(Dataset, db_column='dataset_pk', to_field='dataset', related_name='access_logs')
    action          = EnumField(null=True, values=['access_requested','access_granted','access_revoked','private_link'])
    ts              = DateTimeField()

    class Meta:
        db_table = 'user_access_log'


class UserConsentLog(MySQLModel):
    user_consent_log = PrimaryKeyField(db_column='user_consent_log_pk')
    user             = ForeignKeyField(User, db_column='user_pk', to_field='user', related_name='consent_logs')
    dataset_version  = ForeignKeyField(DatasetVersion, db_column='dataset_version_pk', to_field='dataset_version', related_name='consent_logs')
    ts               = DateTimeField()

    class Meta:
        db_table = 'user_consent_log'


class UserDownloadLog(MySQLModel):
    user_download_log = PrimaryKeyField(db_column='user_download_log_pk')
    user              = ForeignKeyField(User, db_column='user_pk', to_field='user', related_name='download_logs')
    dataset_file      = ForeignKeyField(DatasetFile, db_column='dataset_file_pk', to_field='dataset_file', related_name='download_logs')
    ts                = DateTimeField()

    class Meta:
        db_table = 'user_download_log'

class Checkin(peewee.Model):
    """
    {
      'type': 'checkin',
      'business_id': (encrypted business id),
      'checkin_info': {
            '0-0': (number of checkins from 00:00 to 01:00 on all Sundays),
            '1-0': (number of checkins from 01:00 to 02:00 on all Sundays), 
            ... 
            '14-4': (number of checkins from 14:00 to 15:00 on all Thursdays),
            ...
            '23-6': (number of checkins from 23:00 to 00:00 on all Saturdays)
      } # if there was no checkin for an hour-day block it will not be in the dict
    }
    """
    cid = peewee.PrimaryKeyField()
    business_id = peewee.CharField()
    sunday_count = peewee.IntegerField(default=0)
    monday_count = peewee.IntegerField(default=0)
    tuesday_count = peewee.IntegerField(default=0)
    wednesday_count = peewee.IntegerField(default=0)
    thursday_count = peewee.IntegerField(default=0)
    friday_count = peewee.IntegerField(default=0)
    saturday_count = peewee.IntegerField(default=0)

    class Meta:
        database = db

class Tip(peewee.Model):
    """
    {
        'type': 'tip',