Integrate TiDB Vector Search with SQLAlchemy

This tutorial walks you through how to use SQLAlchemy to interact with TiDB Vector Search, store embeddings, and perform vector search queries.

Prerequisites

To complete this tutorial, you need:

• Python 3.8 or higher installed.
• Git installed.
• A TiDB cluster.

If you don't have a TiDB cluster, you can create one as follows:

• Follow Deploy a local test TiDB cluster or Deploy a production TiDB cluster to create a local cluster.
• Follow Creating a TiDB Cloud Serverless cluster to create your own TiDB Cloud cluster.

Run the sample app

You can quickly learn about how to integrate TiDB Vector Search with SQLAlchemy by following the steps below.

Step 1. Clone the repository

Clone the tidb-vector-python repository to your local machine:

git clone https://github.com/pingcap/tidb-vector-python.git

Step 2. Create a virtual environment

Create a virtual environment for your project:

cd tidb-vector-python/examples/orm-sqlalchemy-quickstart
python3 -m venv .venv
source .venv/bin/activate

Step 3. Install the required dependencies

Install the required dependencies for the demo project:

pip install -r requirements.txt

Alternatively, you can install the following packages for your project:

pip install pymysql python-dotenv sqlalchemy tidb-vector

Step 4. Configure the environment variables

Configure the environment variables depending on the TiDB deployment option you've selected.

• TiDB Cloud Serverless
• TiDB Self-Managed

TIDB_DATABASE_URL="mysql+pymysql://<USER>:<PASSWORD>@<HOST>:<PORT>/<DATABASE>"
# For example: TIDB_DATABASE_URL="mysql+pymysql://root@127.0.0.1:4000/test"

Step 5. Run the demo

python sqlalchemy-quickstart.py

Example output:

Get 3-nearest neighbor documents:
  - distance: 0.00853986601633272
    document: fish
  - distance: 0.12712843905603044
    document: dog
  - distance: 0.7327387580875756
    document: tree
Get documents within a certain distance:
  - distance: 0.00853986601633272
    document: fish
  - distance: 0.12712843905603044
    document: dog

Sample code snippets

You can refer to the following sample code snippets to develop your application.

Create vector tables

Connect to TiDB cluster

import os
import dotenv

from sqlalchemy import Column, Integer, create_engine, Text
from sqlalchemy.orm import declarative_base, Session
from tidb_vector.sqlalchemy import VectorType

dotenv.load_dotenv()

tidb_connection_string = os.environ['TIDB_DATABASE_URL']
engine = create_engine(tidb_connection_string)

Define a vector column

Create a table with a column named embedding that stores a 3-dimensional vector.

Base = declarative_base()

class Document(Base):
    __tablename__ = 'sqlalchemy_demo_documents'
    id = Column(Integer, primary_key=True)
    content = Column(Text)
    embedding = Column(VectorType(3))

Store documents with embeddings

with Session(engine) as session:
   session.add(Document(content="dog", embedding=[1, 2, 1]))
   session.add(Document(content="fish", embedding=[1, 2, 4]))
   session.add(Document(content="tree", embedding=[1, 0, 0]))
   session.commit()

Search the nearest neighbor documents

Search for the top-3 documents that are semantically closest to the query vector [1, 2, 3] based on the cosine distance function.

with Session(engine) as session:
   distance = Document.embedding.cosine_distance([1, 2, 3]).label('distance')
   results = session.query(
      Document, distance
   ).order_by(distance).limit(3).all()

Search documents within a certain distance

Search for documents whose cosine distance from the query vector [1, 2, 3] is less than 0.2.

with Session(engine) as session:
    distance = Document.embedding.cosine_distance([1, 2, 3]).label('distance')
    results = session.query(
        Document, distance
    ).filter(distance < 0.2).order_by(distance).limit(3).all()

See also

• Vector Data Types
• Vector Search Index