Attribute Reference¶

All Data Store attributes live in the Deepstaging.DataStore namespace. See also the Generated Code and Effects Composition pages for what these attributes produce.

[DataStore]¶

Marks a static partial class as the data store container. Only one [DataStore] per assembly is allowed.

[DataStore]
public static partial class AppStore;

[StoredEntity]¶

Marks a class or record as a persistent entity. The entity must have a property with a [TypedId] type, which becomes the primary key.

[StoredEntity]
public partial record Article(ArticleId Id, string Title, string Body);

[ForeignKey<TEntity>]¶

Declares a relationship between stored entities. The generic parameter must reference another [StoredEntity].

[StoredEntity]
public partial record Comment(
    CommentId Id,
    [ForeignKey<Article>] ArticleId ArticleId,
    string Body);

[CompositeKey]¶

Declares a composite primary key instead of a single [TypedId] property. The named properties must exist on the entity.

[StoredEntity]
[CompositeKey(nameof(UserId), nameof(ArticleId))]
public partial record Bookmark(UserId UserId, ArticleId ArticleId, DateTimeOffset CreatedAt);

For composite key entities, GetByIdAsync and DeleteAsync accept all key properties as separate parameters. See Generated Code for the generated interface shape.

[Lookup]¶

Marks a property for indexed lookup. The generator emits a GetBy{Property} method returning StoreQuery<T> on the store interface and all implementations. In the Postgres layer, HasIndex is also configured on the property in OnModelCreating.

[StoredEntity]
public partial record CatalogItem(
    CatalogItemId Id,
    string Name,
    [Lookup] CatalogBrandId BrandId);

This generates:

// On ICatalogItemStore — returns a composable query with the lookup predicate pre-applied
StoreQuery<CatalogItem> GetByCatalogBrandId(CatalogBrandId catalogBrandId);

// Usage — further filter, sort, paginate as needed
var page = await store.GetByCatalogBrandId(brandId)
    .OrderBy(i => i.Name)
    .ToPageAsync(1, 20);

On the effects layer, five terminal methods are generated per lookup:

// All accept optional additional filter/orderBy
CatalogStore.CatalogItems.QueryPageByBrandId<RT>(brandId, page, pageSize, filter?, orderBy?)
CatalogStore.CatalogItems.QueryListByBrandId<RT>(brandId, filter?, orderBy?)
CatalogStore.CatalogItems.QueryCursorByBrandId<RT>(brandId, cursor, limit, filter?)
CatalogStore.CatalogItems.QueryFirstByBrandId<RT>(brandId, filter?)
CatalogStore.CatalogItems.QueryCountByBrandId<RT>(brandId, filter?)

And in the Postgres DbContext:

modelBuilder.Entity<CatalogItem>().HasIndex(e => e.BrandId);

Rules and Constraints¶

• Exactly one [DataStore] per assembly — it acts as the root container for all entities.
• Every [StoredEntity] must be partial so the generator can extend it.
• Every [StoredEntity] needs either a [TypedId] property or a [CompositeKey] attribute.
• [ForeignKey<T>] targets must themselves be [StoredEntity] types.
• The [DataStore] class should be static (warning if not) and must be partial (error if not).