Data Integrity: Raise error on attempt to delete an object required via a Relationship #533
Description
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
class Contact(SQLModel, table=True):
"""An entry in the address book."""
id: Optional[int] = Field(default=None, primary_key=True)
first_name: Optional[str]
last_name: Optional[str]
company: Optional[str]
email: Optional[str]
address_id: Optional[int] = Field(default=None, foreign_key="address.id")
address: Optional[Address] = Relationship(
back_populates="contacts", sa_relationship_kwargs={"lazy": "subquery"}
)
invoicing_contact_of: List["Client"] = Relationship(
back_populates="invoicing_contact", sa_relationship_kwargs={"lazy": "subquery"}
)
class Client(SQLModel, table=True):
"""A client the freelancer has contracted with."""
id: Optional[int] = Field(default=None, primary_key=True)
name: str = Field(default="")
# Client 1:1 invoicing Contact
invoicing_contact_id: int = Field(default=None, foreign_key="contact.id")
invoicing_contact: Contact = Relationship(
back_populates="invoicing_contact_of",
sa_relationship_kwargs={"lazy": "subquery"},
)
contracts: List["Contract"] = Relationship(
back_populates="client", sa_relationship_kwargs={"lazy": "subquery"}
)Description
(As far as I know the documentation does not handle data integrity topics - please point me to the chapter if I am wrong.)
Consider these two model classes Contact and Client. To keep the integrity of the data model, I need the following behavior:
An exception is raised if there is an attempt to delete a Contact that is still the invoicing contact of an existing Client.
Does SQLModel support this, perhaps via SQLAlchemy?
Operating System
macOS
Operating System Details
No response
SQLModel Version
0.0.8
Python Version
3.10
Additional Context
No response