Repository: langchain
Issue: PydanticUserError: SQLDatabaseToolkit is not fully defined; you should define Callbacks, then call SQLDatabaseToolkit.model_rebuild().
Labels: investigate,Ɑ:  core

### Checked other resources

- [x] I added a very descriptive title to this issue.
- [x] I searched the LangChain documentation with the integrated search.
- [x] I used the GitHub search to find a similar question and didn't find it.
- [x] I am sure that this is a bug in LangChain rather than my code.
- [x] The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).

### Example Code

```python

pip install "autogen-ext[azure]" python-dotenv langchain-community psycopg2 langchain_openai langchain_experimental "autogen-core" "autogen-agentchat"

from dotenv import load_dotenv
import os
from langchain_community.utilities.sql_database import SQLDatabase
import psycopg2
from langchain_openai import AzureChatOpenAI
from langchain_experimental.sql import SQLDatabaseChain
from langchain_experimental.sql.base import SQLDatabaseChain
from langchain.cache import InMemoryCache

# Load environment variables from the .env file from the same directory as notebook 
load_dotenv()

# Retrieve environment variables
POSTGRES_USER = os.getenv('POSTGRES_USER')
POSTGRES_PASSWORD = os.getenv('POSTGRES_PASSWORD')
POSTGRES_HOST = os.getenv('POSTGRES_HOST')
POSTGRES_PORT = os.getenv('POSTGRES_PORT')
POSTGRES_DB = os.getenv('POSTGRES_DB')
AZURE_OPENAI_KEY = os.getenv('AZURE_OPENAI_KEY')
AZURE_OPENAI_ENDPOINT = os.getenv('AZURE_OPENAI_ENDPOINT')
AZURE_OPENAI_DEPLOYMENT = os.getenv('AZURE_OPENAI_DEPLOYMENT')

llm_config = {
    "config_list": [
        {
        "model": AZURE_OPENAI_DEPLOYMENT,
        "temperature": 0.7,
        "api_key": AZURE_OPENAI_KEY,
        "azure_endpoint": AZURE_OPENAI_ENDPOINT,
        "api_type": "azure",
        "api_version": "2024-10-21"
        }]}

shipment_db_uri = f"postgresql+psycopg2://{POSTGRES_USER}:{POSTGRES_PASSWORD}@{POSTGRES_HOST}:{POSTGRES_PORT}/{POSTGRES_DB}"

shipment_chain = SQLDatabaseChain(llm=azure_llm, database=shipment_db, verbose=True)
```

### Error Message and Stack Trace (if applicable)

---------------------------------------------------------------------------
PydanticUserError                         Traceback (most recent call last)
Cell In[22], [line 116](vscode-notebook-cell:?execution_count=22&line=116)
      [2](vscode-notebook-cell:?execution_count=22&line=2) llm_config = {
      [3](vscode-notebook-cell:?execution_count=22&line=3)     "config_list": [
      [4](vscode-notebook-cell:?execution_count=22&line=4)         {
   (...)
    [111](vscode-notebook-cell:?execution_count=22&line=111)     ]
    [112](vscode-notebook-cell:?execution_count=22&line=112) }
    [115](vscode-notebook-cell:?execution_count=22&line=115) # Initialize the database chains
--> [116](vscode-notebook-cell:?execution_count=22&line=116) shipment_chain = SQLDatabaseChain(llm=azure_llm, database=shipment_db, verbose=True)
    [117](vscode-notebook-cell:?execution_count=22&line=117) crm_chain = SQLDatabaseChain(llm=azure_llm, database=crm_db, verbose=True)
    [119](vscode-notebook-cell:?execution_count=22&line=119) # Create assistant agents

File ~/Projects/multi-AI-test/azure-postgresql-openai-langchain-autogen-demo/new_env_0.4/lib/python3.12/site-packages/langchain_core/load/serializable.py:125, in Serializable.__init__(self, *args, **kwargs)
    [123](https://file+.vscode-resource.vscode-cdn.net/Users/arnaudcomet/Projects/multi-AI-test/azure-postgresql-openai-langchain-autogen-demo/~/Projects/multi-AI-test/azure-postgresql-openai-langchain-autogen-demo/new_env_0.4/lib/python3.12/site-packages/langchain_core/load/serializable.py:123) def __init__(self, *args: Any, **kwargs: Any) -> None:
    [124](https://file+.vscode-resource.vscode-cdn.net/Users/arnaudcomet/Projects/multi-AI-test/azure-postgresql-openai-langchain-autogen-demo/~/Projects/multi-AI-test/azure-postgresql-openai-langchain-autogen-demo/new_env_0.4/lib/python3.12/site-packages/langchain_core/load/serializable.py:124)     """"""
--> [125](https://file+.vscode-resource.vscode-cdn.net/Users/arnaudcomet/Projects/multi-AI-test/azure-postgresql-openai-langchain-autogen-demo/~/Projects/multi-AI-test/azure-postgresql-openai-langchain-autogen-demo/new_env_0.4/lib/python3.12/site-packages/langchain_core/load/serializable.py:125)     super().__init__(*args, **kwargs)

    [... skipping hidden 1 frame]

File ~/Projects/multi-AI-test/azure-postgresql-openai-langchain-autogen-demo/new_env_0.4/lib/python3.12/site-packages/pydantic/_internal/_mock_val_ser.py:100, in MockValSer.__getattr__(self, item)
     [98](https://file+.vscode-resource.vscode-cdn.net/Users/arnaudcomet/Projects/multi-AI-test/azure-postgresql-openai-langchain-autogen-demo/~/Projects/multi-AI-test/azure-postgresql-openai-langchain-autogen-demo/new_env_0.4/lib/python3.12/site-packages/pydantic/_internal/_mock_val_ser.py:98) # raise an AttributeError if `item` doesn't exist
     [99](https://file+.vscode-resource.vscode-cdn.net/Users/arnaudcomet/Projects/multi-AI-test/azure-postgresql-openai-langchain-autogen-demo/~/Projects/multi-AI-test/azure-postgresql-openai-langchain-autogen-demo/new_env_0.4/lib/python3.12/site-packages/pydantic/_internal/_mock_val_ser.py:99) getattr(self._val_or_ser, item)
--> [100](https://file+.vscode-resource.vscode-cdn.net/Users/arnaudcomet/Projects/multi-AI-test/azure-postgresql-openai-langchain-autogen-demo/~/Projects/multi-AI-test/azure-postgresql-openai-langchain-autogen-demo/new_env_0.4/lib/python3.12/site-packages/pydantic/_internal/_mock_val_ser.py:100) raise PydanticUserError(self._error_message, code=self._code)

PydanticUserError: `SQLDatabaseChain` is not fully defined; you should define `BaseCache`, then call `SQLDatabaseChain.model_rebuild()`.

### Description

I saw this issue: [https://github.com/langchain-ai/langchain/pull/28297](https://github.com/langchain-ai/langchain/issues/28284) and that one ([https://github.com/langchain-ai/langchain/pull/28297](https://github.com/langchain-ai/langchain/pull/28297)) looked like it solved but it hasn't for me. I have to go back to 2.9.2 but now it's not compatible with autogen 0.4 and I have to get to the latest version.

### System Info

System Information
------------------
> OS:  Darwin
> OS Version:  Darwin Kernel Version 24.2.0: Fri Dec  6 19:02:41 PST 2024; root:xnu-11215.61.5~2/RELEASE_ARM64_T6030
> Python Version:  3.12.8 (main, Dec  3 2024, 18:42:41) [Clang 16.0.0 (clang-1600.0.26.4)]

Package Information
-------------------
> langchain_core: 0.3.29
> langchain: 0.3.14
> langchain_community: 0.3.14
> langsmith: 0.2.10
> langchain_experimental: 0.3.4
> langchain_openai: 0.3.0
> langchain_text_splitters: 0.3.5

Optional packages not installed
-------------------------------
> langserve

Other Dependencies
------------------
> aiohttp: 3.11.11
> async-timeout: Installed. No version info available.
> dataclasses-json: 0.6.7
> httpx: 0.28.1
> httpx-sse: 0.4.0
> jsonpatch: 1.33
> langsmith-pyo3: Installed. No version info available.
> numpy: 2.2.1
> openai: 1.59.7
> orjson: 3.10.14
> packaging: 24.2
> pydantic: 2.10.0
> pydantic-settings: 2.7.1
> PyYAML: 6.0.2
> requests: 2.32.3
> requests-toolbelt: 1.0.0
> SQLAlchemy: 2.0.37
> tenacity: 9.0.0
> tiktoken: 0.8.0
> typing-extensions: 4.12.2
> zstandard: Installed. No version info available.