langchain/langchain/vectorstores/_pgvector_data_models.py

from typing import Optional, Tuple

import sqlalchemy
from pgvector.sqlalchemy import Vector
from sqlalchemy.dialects.postgresql import JSON, UUID
from sqlalchemy.orm import Session, relationship

from langchain.vectorstores.pgvector import BaseModel


class CollectionStore(BaseModel):
    __tablename__ = "langchain_pg_collection"

    name = sqlalchemy.Column(sqlalchemy.String)
    cmetadata = sqlalchemy.Column(JSON)

    embeddings = relationship(
        "EmbeddingStore",
        back_populates="collection",
        passive_deletes=True,
    )

    @classmethod
    def get_by_name(cls, session: Session, name: str) -> Optional["CollectionStore"]:
        return session.query(cls).filter(cls.name == name).first()  # type: ignore

    @classmethod
    def get_or_create(
        cls,
        session: Session,
        name: str,
        cmetadata: Optional[dict] = None,
    ) -> Tuple["CollectionStore", bool]:
        """
        Get or create a collection.
        Returns [Collection, bool] where the bool is True if the collection was created.
        """
        created = False
        collection = cls.get_by_name(session, name)
        if collection:
            return collection, created

        collection = cls(name=name, cmetadata=cmetadata)
        session.add(collection)
        session.commit()
        created = True
        return collection, created


class EmbeddingStore(BaseModel):
    __tablename__ = "langchain_pg_embedding"

    collection_id = sqlalchemy.Column(
        UUID(as_uuid=True),
        sqlalchemy.ForeignKey(
            f"{CollectionStore.__tablename__}.uuid",
            ondelete="CASCADE",
        ),
    )
    collection = relationship(CollectionStore, back_populates="embeddings")

    embedding: Vector = sqlalchemy.Column(Vector(None))
    document = sqlalchemy.Column(sqlalchemy.String, nullable=True)
    cmetadata = sqlalchemy.Column(JSON, nullable=True)

    # custom_id : any user defined id
    custom_id = sqlalchemy.Column(sqlalchemy.String, nullable=True)