peewee.InterfaceError: Error, database must be initialized before opening a connection.
If you had taken a moment to debug this, you would have found that `db_name = os.environ.get('DB_NAME')` is somehow getting set to `None`. This is the issue. In debug, I'm getting my DB name in "db_name = os.environ.get('DB_NAME')" but
don't know how to rectify this now. please don't mind this I'm new to
programming might sound silly.

On Sun, Feb 26, 2023 at 4:13 AM Charles Leifer ***@***.***>
wrote:

> If you had taken a moment to debug this, you would have found that db_name
> = os.environ.get('DB_NAME') is somehow getting set to None. This is the
> issue.
>
> —
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 You would want to double-check what you're specifying wherever you have your `PostgresqlDatabase(...)` constructor, e.g.:

```
assert db_name, 'db_name is empty!'
pg_db = PostgresqlExtDatabase(db_name, user=db_user, password=db_password,host=db_host, port=db_port)
``` Thank you for your help, I'll check it out.

On Sun, Feb 26, 2023 at 4:27 AM Charles Leifer ***@***.***>
wrote:

> You would want to double-check what you're specifying wherever you have
> your PostgresqlDatabase(...) constructor, e.g.:
>
> assert db_name, 'db_name is empty!'
> pg_db = PostgresqlExtDatabase(db_name, user=db_user, password=db_password,host=db_host, port=db_port)
>
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 After migration do I need to remove migrate(.... ) function from my model
file?

How will I add new model field in my existing model class(python code)?

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 ```class User(Model):
    pass

f = TextField()
User._meta.add_field('username', f)
print(User._meta.fields)# {'id': <peewee.AutoField at
0x7f552815bc50>,#  'username': <peewee.TextField at 0x7f552b1d7e10>}
```


I've read one reply of yours in which you are referring to this. Is
that referring to what I want.


On Mon, Feb 27, 2023 at 1:07 AM Naveen Pandia ***@***.***>
wrote:

> After migration do I need to remove migrate(.... ) function from my model
> file?
>
> How will I add new model field in my existing model class(python code)?
>

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import os
from playhouse.postgres_ext import CharField, DateTimeField, IntegerField, BooleanField
from .base import Base
import datetime
from peewee import PostgresqlDatabase
from playhouse.migrate import *

db_name = os.environ.get('DB_NAME')
db_host = os.environ.get('DB_HOST')
db_port = os.environ.get('DB_PORT')
db_password = os.environ.get('DB_PASSWORD')
db_user= os.environ.get('DB_USER')
# Initialize database.

pg_db = PostgresqlExtDatabase(db_name, user=db_user, password=db_password,host=db_host, port=db_port)
migrator = PostgresqlMigrator(pg_db)

class EmpDetails(Base):
    id = CharField(25, null=False)
    email = CharField(255, unique=True)
    name = CharField(255)
    location = CharField(255)
    created_at = DateTimeField(default=datetime.datetime.now)
    updated_at = DateTimeField(default=datetime.datetime.now)
    is_active = BooleanField(default=True)
    role = CharField(25)

    class Meta:
        table_name = 'emp_details'

test_field = CharField(default='') 

migrate(
    
    migrator.add_column('emp_details', 'test', test_field),
)

I'm trying to make my DB instance for migration but getting an error :
```
File "/home/naveen.p@ah.zymrinc.com/Desktop/zfr/server/s-venv/lib/python3.8/site-packages/peewee.py", line 3026, in connect
    raise InterfaceError('Error, database must be initialized '
peewee.InterfaceError: Error, database must be initialized before opening a connection.
```