pgvector-dotnet

pgvector support for C#

Supports Npgsql

Getting Started

Run:

dotnet add package Pgvector

And follow the instructions for your database library:

• Npgsql

Npgsql

Import the library

using Pgvector.Npgsql;

Create a table

await using (var cmd = new NpgsqlCommand("CREATE TABLE items (embedding vector(3))", conn))
{
    await cmd.ExecuteNonQueryAsync();
}

Insert a vector

await using (var cmd = new NpgsqlCommand("INSERT INTO items (embedding) VALUES ($1)", conn))
{
    var embedding = new Vector(new float[] { 1, 1, 1 });
    cmd.Parameters.AddWithValue(embedding);
    await cmd.ExecuteNonQueryAsync();
}

Get the nearest neighbors

await using (var cmd = new NpgsqlCommand("SELECT * FROM items ORDER BY embedding <-> $1 LIMIT 5", conn))
{
    var embedding = new Vector(new float[] { 1, 1, 1 });
    cmd.Parameters.AddWithValue(embedding);

    await using (var reader = await cmd.ExecuteReaderAsync())
    {
        while (await reader.ReadAsync())
            Console.WriteLine((Vector) reader.GetValue(0));
    }
}

Add an approximate index

await using (var cmd = new NpgsqlCommand("CREATE INDEX my_index ON items USING ivfflat (embedding vector_l2_ops)", conn))
{
    await cmd.ExecuteNonQueryAsync();
}

Use vector_ip_ops for inner product and vector_cosine_ops for cosine distance

See a full example

Contributing

Everyone is encouraged to help improve this project. Here are a few ways you can help:

• Report bugs
• Fix bugs and submit pull requests
• Write, clarify, or fix documentation
• Suggest or add new features

To get started with development:

git clone https://github.com/pgvector/pgvector-dotnet.git
cd pgvector-dotnet
createdb pgvector_dotnet_test
dotnet test