pgvector support for Npgsql
Get Started
$ dotnet add package PgvectorReadme
pgvector-dotnet
pgvector support for C#
Supports Npgsql
Getting Started
Run:
dotnet add package Pgvector
And follow the instructions for your database library:
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