ExtensionsVectorData lodestarvectorstore collectionexistsasync

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LodestarVectorStore.CollectionExistsAsync

Whether a collection of that name has been created or written to.

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

Parameters — name is the collection asked about. cancellationToken is accepted for the abstraction's sake and not observed: the answer is a dictionary lookup.

Returns — a completed Task<bool>: true when the store holds a collection under name that has been ensured or written to and not deleted since; false otherwise, including for a name the store has never seen.

Example — requested, ensured, deleted.

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

static async Task<string> TrackAsync()
{
    using var store = new LodestarVectorStore();
    VectorStoreCollection<string, Note> notes = store.GetCollection<string, Note>("notes");
    bool requested = await store.CollectionExistsAsync("notes");

    await notes.EnsureCollectionExistsAsync();
    bool ensured = await store.CollectionExistsAsync("notes");

    await store.EnsureCollectionDeletedAsync("notes");
    bool deleted = await store.CollectionExistsAsync("notes");

    return $"{requested} {ensured} {deleted}";
}

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

Remarks — it answers the same question as the collection's own LodestarVectorStoreCollection.CollectionExistsAsync, asked by name. A name the store has never handed out is not an error, since asking whether something exists is how a caller finds out that it does not.

Applies to — net10.0, netstandard2.0.

See also — LodestarVectorStore.ListCollectionNamesAsync, LodestarVectorStore.