LiteDocumentStore 0.5.0

LiteDocumentStore

Turn a single SQLite .db file into a hybrid document + relational store. C# objects are serialized to JSON and stored in SQLite's binary JSONB format, and the same tables stay fully open to raw SQL, joins and indexes — this is deliberately not an opaque document database. Raw ADO.NET over Microsoft.Data.Sqlite, no ORM, no runtime reflection or IL generation, so the library is Native-AOT / trim compatible.

Install

dotnet add package LiteDocumentStore

Requirements: .NET 10, and SQLite 3.45+ for JSONB — the bundled native SQLite already satisfies this, and every connection is checked as it opens, so an older one fails fast with UnsupportedSqliteVersionException instead of no such function: jsonb.

Upgrading from 0.4.0? CHANGELOG.md lists what breaks and what to do about each one — several of the breaks are silent.

Quick start

Register the store through dependency injection and resolve IDocumentStore:

using LiteDocumentStore;
using Microsoft.Extensions.DependencyInjection;

var services = new ServiceCollection();
services.AddLiteDocumentStore(options =>
{
    options.ConnectionString = "Data Source=app.db";
    options.EnableWalMode = true;
    // For Native-AOT, supply source-generated metadata:
    // options.SerializerOptions = new JsonSerializerOptions { TypeInfoResolver = MyJsonContext.Default };
});

await using var provider = services.BuildServiceProvider();
var store = provider.GetRequiredService<IDocumentStore>();

await store.CreateTableAsync<Customer>();
await store.UpsertAsync("c1", new Customer { Name = "Ada", Email = "ada@example.com" });

var customer = await store.GetAsync<Customer>("c1");

Without DI, build the store via IDocumentStoreFactory.CreateAsync(DocumentStoreOptions).

What you get

• Document CRUD (IDocumentStore): type-safe, fully async, table names derived from the type's namespace-qualified name through a pluggable ITableNamingConvention — see Table names below.
• Querying: a JSON-path equality shorthand, plus a composable DocumentQuery<T> builder with comparison, Like/Glob, In, null and array-contains operators, ordering and paging.
• Field-level patching: DocumentPatch<T> changes named fields in one statement, so a concurrent writer's edits to other fields survive — a read-modify-write silently reverts them.
• Optimistic concurrency: every row carries a version; GetWithVersionAsync plus the …WithVersionAsync writes and deletes are compare-and-swap, and a lost race throws ConcurrencyException carrying a ConcurrencyConflictKind to pick a retry strategy from.
• Transactions: BeginTransactionAsync / ExecuteInTransactionAsync, deferred by default with TransactionMode.Immediate available for read-then-write work.
• Blobs: raw binary payloads with content type, timestamps, versioning, prefix listing, and streaming in both directions — including a seekable read stream over SQLite's incremental blob I/O, so a large payload is never materialized.
• Migrations: versioned IMigration steps with checksummed history, applied under a write lock so two processes starting together cannot both run the same migration.
• Indexes: expression indexes over JSON paths, composite and unique variants, partial-index filters, and virtual (generated) columns for hot query paths.
• Native-AOT / trim compatible: <IsAotCompatible>true</IsAotCompatible>; serialization goes through System.Text.Json JsonTypeInfo<T>. Supplied SerializerOptions must carry a TypeInfoResolver — the store resolves types through GetTypeInfo, which never populates a missing one, so options without a resolver are refused when the store is created. Leave SerializerOptions null for the reflection-based fallback.
• Cross-platform: tested on Windows, Linux and macOS.

Querying

// JSON path + value
var byName = await store.QueryAsync<Customer, string>("$.Name", "Ada");

// Composable, and index-aware
var q = DocumentQuery<Customer>.Where("$.Age", QueryOperator.GreaterThanOrEqual, 30)
                               .AndIn("$.City", ["Boston", "Denver"])
                               .AndIsNotNull("$.Email")
                               .OrderBy("$.Age", descending: true)
                               .Skip(10).Take(20);

var adults = await store.QueryAsync(q);
var howMany = await store.CountAsync(q);   // predicates only; ordering and paging are ignored

Predicates combine with AND only. For joins, aggregates, OR groups and virtual-column seeks, drop to raw SQL.

Raw SQL

The connection is on loan for the duration of the callback. GetTableName<T>() gives the table the store uses for T, so nothing is hardcoded, and DeserializeDocument<T>() reads a json(data) column back with the store's own serializer options. Finish any transaction you open in the callback: a connection handed back with one still on it is closed rather than pooled, so the leak costs a connection instead of poisoning the next caller.

var table = store.GetTableName<Customer>();

var adults = await store.ExecuteRawAsync(async (conn, ct) =>
{
    await using var cmd = conn.CreateCommand();
    cmd.CommandText = $"SELECT json(data) FROM [{table}] WHERE json_extract(data, '$.Age') >= @Min";
    cmd.Parameters.AddWithValue("@Min", 18);

    var results = new List<Customer>();
    await using var reader = await cmd.ExecuteReaderAsync(ct);
    while (await reader.ReadAsync(ct))
    {
        var doc = store.DeserializeDocument<Customer>(reader.GetString(0));
        if (doc is not null) results.Add(doc);
    }
    return results;
});

SerializeDocument<T>(value) is the write half: it returns the same UTF-8 JSON bytes the store writes, so a raw INSERT INTO [table] (id, data, version) VALUES (@Id, jsonb(@Data), 1) stores documents the store can read back. All three members are on IDocumentTransaction too.

Create commands with connection.CreateCommand() — a directly constructed new SqliteCommand(sql, connection) leaves Transaction null, and Microsoft.Data.Sqlite refuses to execute it while a transaction is pending.

Concurrency and transactions

IDocumentStore is thread-safe and meant to be a singleton — one per database. It owns a pool of SQLite connections and rents one per operation, so concurrent callers never share a connection handle. Size the pool with DocumentStoreOptions.MaxPoolSize.

A transaction holds one of those connections until it is committed, rolled back or disposed — await using it. One that is never finished holds its slot until the garbage collector finalizes it, which logs the leak at Error and gives the slot back; until then, operations waiting for a connection fail with TimeoutException after DocumentStoreOptions.PoolWaitTimeoutMs (30 s by default, Timeout.Infinite to queue indefinitely) rather than hanging.

Because each operation runs on its own connection, operations called directly on the store each commit on their own. To make several writes atomic, use a transaction and call the operations on it:

await using var tx = await store.BeginTransactionAsync();
await tx.UpsertAsync(order.Id, order);
await tx.PutBlobAsync(order.Id, invoicePdf);
await tx.CommitAsync();   // disposing without committing rolls back

Or let the store handle commit/rollback for you:

await store.ExecuteInTransactionAsync(async tx =>
{
    await tx.UpsertAsync(order.Id, order);
    await tx.DeleteAsync<Draft>(draftId);
});

Transactions are independent: two concurrent transactions run on two connections, so neither can see or roll back the other's writes.

In-memory databases

Use DocumentStoreOptions.ForInMemory() for a private in-memory database, or ForSharedInMemory(name) to share one between stores. A connection string naming a private in-memory database is rejected: it belongs to a single connection, so a pooled store would hand every operation its own empty database. That covers Data Source=:memory: and file::memory: (with or without Cache=Shared), Mode=Memory without a shared cache, and an in-memory URI whose filename is empty — the data source is parsed the way SQLite parses it rather than matched by spelling. ForSharedInMemory(name) rejects a blank name, or one containing ;, ?, & or #, since the name becomes a URI filename. Note that shared-cache in-memory databases lock at table granularity — overlapping write transactions fail with SQLITE_LOCKED, so use a file database for concurrent write workloads.

How it works

• Storage. One table per document type: id TEXT PRIMARY KEY, data BLOB NOT NULL, version INTEGER NOT NULL DEFAULT 1. Writes go through jsonb(@Data) with UTF-8 JSON bytes; reads come back as SELECT json(data). JSONB is binary, so a raw SELECT data is not deserializable.

• Table names. The default ITableNamingConvention uses the type's namespace-qualified name with every separator folded to an underscore, and a constructed generic appends its arity then each argument by the same rule:

  type	table
  Customer (global namespace)	Customer
  MyApp.Sales.Order	MyApp_Sales_Order
  MyApp.Outer+Inner	MyApp_Outer_Inner
  MyApp.Box<int>	MyApp_Box_1_System_Int32

  Never hardcode a table name — ask the store: store.GetTableName<T>(), on a transaction too. The fold is deliberately collision-resistant rather than injective, so a store additionally refuses to serve two different types that resolve to one table name (which would otherwise make each type's writes overwrite the other's rows silently; names differing only in ASCII case count as one, since SQLite reads them as one table). Types the default cannot name — open generic definitions, generic parameters, arrays, pointers, by-ref types, types nested in a generic, and non-ASCII names — throw NotSupportedException naming the type. Supply your own convention through DocumentStoreOptions.TableNamingConvention or WithTableNamingConvention; to keep names an earlier version wrote, that is five lines:

  internal sealed class SimpleTypeNameConvention : ITableNamingConvention
  {
      public string GetTableName<T>() => GetTableName(typeof(T));
  
      public string GetTableName(Type type) => type.Name;
  }
  

  An existing database keeps the tables it has, so switching to the folded default means renaming them (or plugging the convention above). The same applies to raw SQL inside your own IMigration implementations, and to auto-derived index names, which embed the table name (next bullet).

• Index names. An index created without an explicit indexName is called idx_{table}_{path}_{digest}: the path with its leading $. dropped and its remaining . separators folded to _, then six lowercase hex characters — the first three bytes of a SHA-256 over the derivation kind, the table name and the paths, U+0000-delimited. So CreateIndexAsync<Customer>(x => x.Email) derives idx_Customer_Email_3cf60a, while the index AddVirtualColumnAsync<Customer>("$.Email", "Email", …) puts on its generated column is idx_Customer_Email_4ee840: the readable halves are one name and only the digest tells the two apart — which matters, because an index on the generated column does not serve a query on the raw expression. The digest is collision-resistant rather than injective (24 bits is not a proof), so a name already held by a different definition is still refused rather than silently adopted. A path whose readable half is no SQL identifier — $.Tags[0], $.full-name, $."a.b" — has no derived name at all and needs an explicit one.

  The digest is new in 0.5.0, so every auto-derived index name changes on an existing database: idx_Customer_Email is now idx_Customer_Email_3cf60a. Two consequences, both silent:

  • DropIndexAsync<T>(x => x.Email) derives the new name, which nothing in an upgraded database holds. Both drop overloads are IF EXISTS, so the call succeeds without dropping anything. Drop the old index through the string overload instead: DropIndexAsync("idx_Customer_Email").
  • CreateIndexAsync<T>(x => x.Email) also derives the new name, and the sqlite_master definition pre-check compares per name, so it neither finds nor refuses the old-named index over the same expression. The new index is created beside it and the database ends up carrying two indexes over one path, paying the write cost of both on every insert and update.

  So list the old names once and drop each explicitly before re-creating anything:

  SELECT name FROM sqlite_master WHERE type = 'index' AND name LIKE 'idx\_%' ESCAPE '\';
  

• Safety. All values are parameterized. SQL identifiers and JSON paths cannot be bound, so they are interpolated — and validated first, in one place: table/index/column names must match [A-Za-z_][A-Za-z0-9_]*, JSON paths must match $(.member|[index])*, and column types come from a five-entry whitelist. JSON paths are interpolated on purpose: SQLite only matches a query against an expression index when the indexed expression appears literally, so binding the path would silently disable every index the store creates. ExecuteRawAsync is the escape hatch, and SQL you write there is yours to parameterize.

• Connections. The store opens and PRAGMA-configures connections once, then rents one per operation from its own pool. WAL and synchronous = NORMAL are the defaults; an option the database cannot honour (page size, WAL on an in-memory DB) is refused at open rather than silently ignored.

Dependencies

• .NET 10
• Microsoft.Data.Sqlite
• SQLitePCLRaw.lib.e_sqlite3 — referenced directly and pinned, rather than taken transitively, to keep the native SQLite on a version without known advisories
• Microsoft.Extensions.DependencyInjection.Abstractions / Logging.Abstractions

CI/CD

• Continuous Integration: builds, unit + integration tests, and every example run on each push and PR, with a coverage floor that fails the build
• Multi-platform Testing: tests run on Ubuntu, Windows and macOS
• Packaging: the package is packed and its contents asserted on every run; a Native AOT publish of examples/AotVerification proves the AOT claim by running the binary
• Code Quality: formatting and static analysis, plus a CodeQL security scan
• NuGet Publishing: automated on GitHub releases, with build provenance attestation
• Dependency Updates: Dependabot keeps dependencies up to date, and CI fails on a vulnerable one

See .github/WORKFLOWS.md for detailed CI/CD documentation.

Contributing

Contributions are welcome. The solution is at the repository root, so nothing needs a cd:

dotnet build --configuration Release
dotnet test tests/LiteDocumentStore.UnitTests/LiteDocumentStore.UnitTests.csproj
dotnet test tests/LiteDocumentStore.IntegrationTests/LiteDocumentStore.IntegrationTests.csproj
dotnet run --project examples/Examples -- all

Then:

1. Fork the repository
2. Create a feature branch
3. Make your changes, with both a unit and an integration test
4. Make sure dotnet test and dotnet format --verify-no-changes pass
5. Submit a pull request

CI will automatically validate your changes.

License

This project is licensed under the MIT License - see the LICENSE file for details.