ExtensionsVectorData lodestarvectorstorecollection collectionexistsasync

Development build. This page describes main, not a released package. The latest published Lodestar.Extensions.VectorData is 0.1.0 — read its documentation.

Home › ExtensionsVectorData › Vector store

LodestarVectorStoreCollection.CollectionExistsAsync

Whether the collection has been ensured or written to.

public Task<bool> CollectionExistsAsync(CancellationToken cancellationToken = default)

Parameters — cancellationToken is checked on entry: one already cancelled returns a cancelled task (#1354).

Returns — a completed Task<bool>: true once LodestarVectorStoreCollection.EnsureCollectionExistsAsync or an upsert has run, and false again after LodestarVectorStoreCollection.EnsureCollectionDeletedAsync.

Example — an upsert is enough to make a collection exist.

using Lodestar.Extensions.VectorData;
using Microsoft.Extensions.VectorData;

static async Task<string> ExistAsync()
{
    using var notes = new LodestarVectorStoreCollection<string, Note>("notes");
    bool constructed = await notes.CollectionExistsAsync();

    await notes.UpsertAsync(new Note { Id = "a", Text = "a note", Embedding = new float[] { 1f, 0f, 0f } });
    bool written = await notes.CollectionExistsAsync();

    return $"{constructed} {written}";
}

string states = ExistAsync().GetAwaiter().GetResult();  // => False True

Remarks — a server-backed provider answers this by asking the server whether a table or an index is there. An in-process collection has nothing to ask, so existence is a flag the collection keeps, set and cleared exactly where the abstraction says a server's would be. That is what lets code written against the abstraction run unchanged against this store.

Deleting every record does not clear it; only deleting the collection does.

Applies to — net10.0, netstandard2.0.

See also — LodestarVectorStore.CollectionExistsAsync, LodestarVectorStoreCollection.