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Marks the collection as existing.

public Task EnsureCollectionExistsAsync(CancellationToken cancellationToken = default)

Parameters — cancellationToken is checked before the collection is marked as existing.

Returns — a completed Task, or a cancelled one, changing nothing, when cancellationToken is already cancelled (#1354).

Example — an empty collection that exists, and is listed.

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

static async Task<string> EnsureAsync()
{
    using var store = new LodestarVectorStore();
    VectorStoreCollection<string, Note> notes = store.GetCollection<string, Note>("notes");

    await notes.EnsureCollectionExistsAsync();
    await notes.EnsureCollectionExistsAsync();

    List<string> names = await store.ListCollectionNamesAsync().ToListAsync();
    return string.Join(",", names);
}

string listed = EnsureAsync().GetAwaiter().GetResult();  // => notes

Remarks — calling it on a collection that already exists does nothing, and it never touches the records: ensuring a collection that holds records keeps every one of them. A consumer written against the abstraction calls this before its first write, because a server-backed store needs the table created; here it only sets the flag LodestarVectorStoreCollection.CollectionExistsAsync reads, and an upsert would have set it anyway.

Applies to — net10.0, netstandard2.0.

See also — LodestarVectorStoreCollection.EnsureCollectionDeletedAsync, LodestarVectorStoreCollection.