Currently im developing a website using flask as the backend and i got kind of stuck in thi problem. So i’m developing a function to create a new data. For clearer understanding, this is how i illustrate the model of the related data

• KekayaanIntelektual is the parent model (and table) for HakCipta and Paten
• KekayaanIntelektual has many to many relationship with Inventor, Pemegang, RiwayatKerjaSama

The function i create is for HakCipta model, and this is the model

from exts import db
import uuid
from models import KekayaanIntelektual

class HakCipta(KekayaanIntelektual):
    __tablename__ = 'hak_cipta'
    ID_KI = db.Column(db.String(36), db.ForeignKey('kekayaan_intelektual.ID_KI'), primary_key=True)
    
    NO_PENCATATAN = db.Column(db.String(50), nullable=True)
    TGL_PENCATATAN = db.Column(db.DateTime, nullable=True)
    JENIS_CIPTAAN = db.Column(db.String(25), nullable=True)

    __mapper_args__ = {
        'polymorphic_identity': 'hak_cipta',
    }

and this is the model for KekayaanIntelektual

from exts import db
from models import has_ki
from models import create_ki
import uuid

class KekayaanIntelektual(db.Model):
    __tablename__ = 'kekayaan_intelektual'
    ID_KI = db.Column(db.String(36), primary_key=True, default=str(uuid.uuid4))
    NO_PERMOHONAN_KI = db.Column(db.String(50), nullable=True)
    TGL_PERMOHONAN = db.Column(db.DateTime, nullable=True)
    JUDUL = db.Column(db.String(50), nullable=False)
    ABSTRAK = db.Column(db.Text, nullable=False)
    TGL_AWAL_PERLINDUNGAN = db.Column(db.DateTime, nullable=True)
    TGL_AKHIR_PERLINDUNGAN = db.Column(db.DateTime, nullable=True)
    STATUS = db.Column(db.String(20), nullable=False)
    JENIS_KI = db.Column(db.String(50), nullable=False)

    pemegangs = db.relationship('Pemegang', secondary='has_ki', backref=db.backref('kekayaan_intelektual', lazy=True))
    form_ketertarikan = db.relationship('FormKetertarikan', backref='form_ketertarikan', lazy=True)
    riwayat_kerja_sama = db.relationship('RiwayatKerjaSama', backref='riwayat_kerja_sama', lazy=True)
    gambar_ki = db.relationship('GambarKi', backref='gambar_ki', lazy=True)
    inventors = db.relationship('Inventor', secondary='create_ki', lazy='subquery', backref=db.backref('kekayaan_intelektual', lazy=True))
    hak_cipta = db.relationship('HakCipta', backref=db.backref('kekayaan_intelektual', lazy=True))

    __mapper_args__ = {
        'polymorphic_on': JENIS_KI,
        'polymorphic_identity': 'kekayaan_intelektual',
        'with_polymorphic': '*'
    }

and this is the function

def post(self):
        data = request.get_json()
        
        try:
            print("Received data:", data)
            
         
            new_hak_cipta = HakCipta(
                NO_PERMOHONAN_KI=data.get('NO_PERMOHONAN_KI'),
                TGL_PERMOHONAN=parse_date(data.get('TGL_PERMOHONAN')),
                JUDUL=data['JUDUL'],
                ABSTRAK=data.get('ABSTRAK'),
                TGL_AWAL_PERLINDUNGAN=parse_date(data.get('TGL_AWAL_PERLINDUNGAN')),
                TGL_AKHIR_PERLINDUNGAN=parse_date(data.get('TGL_AKHIR_PERLINDUNGAN')),
                STATUS=data.get('STATUS'),
                JENIS_KI='hak_cipta',  # Set the type here if needed
                # 
                ID_KI = str(generate_uuid()),
                NO_PENCATATAN=data.get('NO_PENCATATAN'),
                TGL_PENCATATAN=parse_date(data.get('TGL_PENCATATAN')),
                JENIS_CIPTAAN=data.get('JENIS_CIPTAAN')
            )
            # new_hak_cipta.hak_cipta.append(new_hak_cipta)

            # Add related entities
            if 'pemegangs' in data:
                pemegangs = Pemegang.query.filter(Pemegang.ID_PEMEGANG.in_(data['pemegangs'])).all()
                # ki.pemegangs.extend(pemegangs)
                new_hak_cipta.pemegangs.extend(pemegangs)

            if 'inventors' in data:
                inventors = Inventor.query.filter(Inventor.NIP_NIM.in_(data['inventors'])).all()
                # ki.inventors.extend(inventors)
                new_hak_cipta.inventors.extend(inventors)

            if 'riwayat_kerja_sama' in data:
                for rks_data in data['riwayat_kerja_sama']:
                    rks = RiwayatKerjaSama(
                        ID_KERJA_SAMA=str(generate_uuid()),
                        TGL_MULAI=parse_date(rks_data.get('TGL_MULAI')),
                        TGL_AKHIR=parse_date(rks_data.get('TGL_AKHIR')),
                        NAMA_INSTITUSI=rks_data['NAMA_INSTITUSI'],
                        ALAMAT=rks_data.get('ALAMAT'),
                        NEGARA=rks_data.get('NEGARA'),
                        DESKRIPSI=rks_data.get('DESKRIPSI'),
                        LOGO_DIR=rks_data.get('LOGO_DIR'),
                        # ID_KI=ki.ID_KI
                    )
                    new_hak_cipta.riwayat_kerja_sama.extend(rks)

            # Add and commit the HakCipta object
            db.session.add(new_hak_cipta)
            print("added hak cipta")
            db.session.commit()
            print("comitted")

            return {
                'message': 'Hak Cipta created successfully',
                'data': new_hak_cipta
            }, 201

        except Exception as e:
            db.session.rollback()
            error_message = str(e)
            traceback.print_exc()
            return {'message': 'An unexpected error occurred: ' + error_message}, 500

i try to insert this data

{
"NO_PERMOHONAN_KI": "1",
"TGL_PERMOHONAN": "2024-06-14 14:38:48",
"JUDUL": "Buku Tatang Sutarman",
"ABSTRAK": "Tatang Sutarman adalah seorang filosofis",
"TGL_AWAL_PERLINDUNGAN": "2024-06-14 14:38:48",
"TGL_AKHIR_PERLINDUNGAN": "2024-06-14 14:38:48",
"STATUS": "Diterima",
"JENIS_KI": "hak_cipta",
"pemegangs": [
"1"
],
"inventors": [
"201524033", "201524054"
],
"NO_PENCATATAN":"NP01",
"TGL_PENCATATAN":"2024-06-20",
"JENIS_CIPTAAN":"Buku"
}

but im getting this error
sqlalchemy.exc.OperationalError: (pymysql.err.OperationalError) (1364, “Field ‘JUDUL’ doesn’t have a default value”)

[SQL: INSERT INTO hak_cipta (`ID_KI`, `NO_PENCATATAN`, `TGL_PENCATATAN`, `JENIS_CIPTAAN`) VALUES (%(ID_KI)s, %(NO_PENCATATAN)s, %(TGL_PENCATATAN)s, %(JENIS_CIPTAAN)s)] 
[parameters: {'ID_KI': 'c349df13-9a90-4883-badf-526540f5cfa1', 'NO_PENCATATAN': 'NP01', 'TGL_PENCATATAN': datetime.datetime(2024, 6, 20, 0, 0), 'JENIS_CIPTAAN': 'Buku'}]
(Background on this error at: https://sqlalche.me/e/20/e3q8)

why am i getting this error? i thought when i create HakCipta and then the instance of KekayaanIntelektual is also generated.