How to use Pickle Type

[RamDurgaSai]

First Check

• I added a very descriptive title to this issue.
• I used the GitHub search to find a similar issue and didn't find it.
• I searched the SQLModel documentation, with the integrated search.
• I already searched in Google "How to X in SQLModel" and didn't find any information.
• I already read and followed all the tutorial in the docs and didn't find an answer.
• I already checked if it is not related to SQLModel but to Pydantic.
• I already checked if it is not related to SQLModel but to SQLAlchemy.

Commit to Help

• I commit to help with one of those options 👆

Example Code

from sqlmodel import SQLModel, Field, PickleType



class FlowInDb(SQLModel, table=True):
    id : str = Field(primary_key=True)
    flow: PickleType
    
    class Config:
        arbitrary_types_allowed = True

Description

Getting Error ...
sqlalchemy.exc.CompileError: (in table 'flowindb', column 'flow'): Can't generate DDL for NullType(); did you forget to specify a type on this Column?

Operating System

Windows

Operating System Details

No response

SQLModel Version

0.06

Python Version

3.10

Additional Context

No response

[byrman]

Try flow: PickleType = Field(sa_column=Column(PickleType)).

[RamDurgaSai]

Try flow: PickleType = Field(sa_column=Column(PickleType)).

Thanks

Gettting ...

sqlalchemy.exc.IntegrityError: (sqlite3.IntegrityError) NOT NULL constraint failed: flowindb.flow
[SQL: INSERT INTO flowindb (flow, id) VALUES (?, ?)]
[parameters: (None, 'd4pgyYaU3nVCJgXjYu6b')]
(Background on this error at: https://sqlalche.me/e/14/gkpj)

[byrman]

My previous answer was perhaps a bit confusing. Suppose flow is of type Foo, then your code becomes:

class Foo:
    pass


class FlowInDb(SQLModel, table=True):
    id : str = Field(primary_key=True)
    flow: Foo = Field(sa_column=Column(PickleType))
    
    class Config:
        arbitrary_types_allowed = True

Then you can insert a FlowInDb instance into the database like this:

session.add(FlowInDb(id="d4pgyYaU3nVCJgXjYu6b", flow=Foo())
session.commit()

You don't have to pickle yourself, PickleType takes care of that.