;
};
## What this error means
`FOREIGN_KEYS_CIRCULAR_DEPENDENCY` means foreign key relationships form a cycle. This can be a self-referencing table or a group of tables that reference each other in a loop.
## Why PlanetScale rejects it
Foreign key cycles can make schema dependency ordering ambiguous. They can also produce unsupported cascaded behavior, especially when all participating constraints use `CASCADE` or `SET NULL` actions.
## How to fix it
Break the cycle where possible:
* Remove one database-enforced foreign key constraint and enforce that relationship in application code.
* Replace cascading actions with explicit application workflows.
* Split schema changes so parent tables and child constraints are introduced in a predictable order.
* For self-references, check whether the constraint is necessary or whether application validation is enough.
Example cycle:
```sql theme={null}
CREATE TABLE teams (
id bigint unsigned NOT NULL,
owner_user_id bigint unsigned NOT NULL,
PRIMARY KEY (id),
CONSTRAINT teams_owner_fk FOREIGN KEY (owner_user_id) REFERENCES users(id)
);
CREATE TABLE users (
id bigint unsigned NOT NULL,
team_id bigint unsigned NOT NULL,
PRIMARY KEY (id),
CONSTRAINT users_team_fk FOREIGN KEY (team_id) REFERENCES teams(id)
);
```
One common fix is to remove one constraint and keep an index for the relationship:
```sql theme={null}
CREATE TABLE users (
id bigint unsigned NOT NULL,
team_id bigint unsigned NOT NULL,
PRIMARY KEY (id),
KEY users_team_idx (team_id)
);
```
## Related docs
* [Foreign key constraints](/docs/vitess/foreign-key-constraints#cyclic-foreign-keys)
* [Operating without foreign key constraints](/docs/vitess/operating-without-foreign-key-constraints)
## Need help?
Get help from [the PlanetScale Support team](https://planetscale.com/contact?initial=support), or join our [Discord community](https://pscale.link/community) to see how others are using PlanetScale.
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