**Description**
The documentation and the error message of the [check-migrations](https://airflow.apache.org/docs/apache-airflow/stable/cli-and-env-variables-ref.html#check-migrations) / `def check_migrations` could be more verbose.  This check can fail if the underlying database was never initialised.


**Use case / motivation**

We are deploying our airflow helm chart with terraform helm provider. This provider has a [bug](https://github.com/hashicorp/terraform-provider-helm/issues/683) with helm hook. If airflow would give us a bit more verbose error message why could the `check-migrations` fail, we would find the underlying error/bug much sooner.


**Are you willing to submit a PR?**
Yes



airflow/utils/db.py
#
#
#
import logging
import os
import time
from sqlalchemy import Table, exc, func
from airflow import settings
from airflow.configuration import conf
from airflow.jobs.base_job import BaseJob  
from airflow.models import (  
    DAG,
    XCOM_RETURN_KEY,
    BaseOperator,
    BaseOperatorLink,
    Connection,
    DagBag,
    DagModel,
    DagPickle,
    DagRun,
    DagTag,
    Log,
    Pool,
    SkipMixin,
    SlaMiss,
    TaskFail,