sqlite-vec/site/using/python.md

title
sqlite-vec in Python

Using sqlite-vec in Python

To use sqlite-vec from Python, install the sqlite-vec PyPi package using your favorite Python package manager:

pip install sqlite-vec

Once installed, use the sqlite_vec.load() function to load sqlite-vec SQL functions into a SQLite connection.

import sqlite3
import sqlite_vec

db = sqlite3.connect(":memory:")
db.enable_load_extension(True)
sqlite_vec.load(db)
db.enable_load_extension(False)

vec_version, = db.execute("select vec_version()").fetchone()
print(f"vec_version={vec_version}")

See simple-python/demo.py for a more complete Python demo.

Working with Vectors

Lists

If your vectors in Python are provided as a list of floats, you can convert them into the compact BLOB format that sqlite-vec uses with serialize_float32(). This will internally call struct.pack().

from sqlite_vec import serialize_float32

embedding = [0.1, 0.2, 0.3, 0.4]
result = db.execute('select vec_length(?)', [serialize_float32(embedding)])

print(result.fetchone()[0]) # 4

NumPy Arrays

If your vectors are NumPy arrays, the Python SQLite package allows you to pass it along as-is, since NumPy arrays implement the Buffer protocol. Make sure you cast your array elements to 32-bit floats with .astype(np.float32), as some embeddings will use np.float64.

import numpy as np
embedding = np.array([0.1, 0.2, 0.3, 0.4])
db.execute(
    "SELECT vec_length(?)", [embedding.astype(np.float32)]
) # 4

Using an up-to-date version of SQLite

Some features of sqlite-vec will require an up-to-date SQLite library. You can see what version of SQLite your Python environment uses with sqlite3.sqlite_version, or with this one-line command:

python -c 'import sqlite3; print(sqlite3.sqlite_version)'

Currently, SQLite version 3.41 or higher is recommended but not required. sqlite-vec will work with older versions, but certain features and queries will only work correctly in >=3.41.

To "upgrade" the SQLite version your Python installation uses, you have a few options.

Compile your own SQLite version

You can compile an up-to-date version of SQLite and use some system environment variables (like LD_PRELOAD and DYLD_LIBRARY_PATH) to force Python to use a different SQLite library. This guide goes into this approach in more details.

Although compiling SQLite can be straightforward, there are a lot of different compilation options to consider, which makes it confusing. This also doesn't work with Windows, which statically compiles its own SQLite library.

Use pysqlite3

pysqlite3 is a 3rd party PyPi package that bundles an up-to-date SQLite library as a separate pip package.

While it's mostly compatible with the Python sqlite3 module, there are a few rare edge cases where the APIs don't match.

Upgrading your Python version

Sometimes installing a latest version of Python will "magically" upgrade your SQLite version as well. This is a nuclear option, as upgrading Python installations can be quite the hassle, but most Python 3.12 builds will have a very recent SQLite version.