Sqlalchemy mysql FLOAT precision and length

Question

I'm trying to model an existing database with SQLAlchemy and I am very close.

My sticking point is the FLOAT types.

In the MySQL database they are Float(10,2)

Using SQLAlchemy, I'm unable to replicate this regardless of how I try to create them.

Examples are:

from sqlalchemy.dialects.mysql import FLOAT
from sqlalchemy.ext.declarative import declarative_base

connection_string = 'xxxxx'

engine = create_engine(connection_string, echo=True, encoding='utf-8')
Base = declarative_base(engine)

class TestTable(Base):
    __tablename__ = 'my_test_table'
    float_1 = Column(FLOAT(length=10, precision=2))
    float_2 = Column(Float(10,2))
    float_3 = Column(Float(as_decimal=True))

Answer 1

If you want to get adaptative scale, instead of fixed, I would suggest to use as follows:

lat = Column(FLOAT(precision=10, decimal_return_scale=None))

More specifically, let's consider following lat float: 45.7421773

Here are parameters possibility:

lat_precision_adaptative_scale = Column(FLOAT(precision=32, decimal_return_scale=None))
lat_precision_fixed_scale = Column(FLOAT(precision=32, scale=10))
lat_no_precision_fixed_scale = Column(FLOAT(scale=3))
lat = Column(FLOAT)

It will insert following results:

Hope it helps!

Answer 2

I think I'm right in saying that you're trying to set precision and scale? Have you tried:

float = Column(FLOAT(precision=10, scale=2))

Your definitions of float_2 and float_3 don't appear to be using the imported MySQL dialect FLOAT class, and may be using another class here which may be adding to the confusion!