LODDE 0.2.0

LuxxyDaizy Database Engine (LODDE)

Overview

• A C# class library database that can be added directly to a project, with a LINQ interface for CRUD, persisting data to local files.

Requirements

• .NET 10
• Persists data to disk (binary, encrypted)

Features

• Embedded, per-project — no server; each project creates its own LoddeDatabase pointed at its own data directory with its own password, configured through LoddeOptions.
• LINQ everywhere — LoddeCollection<T> implements IEnumerable<T>, so Where, Select, OrderBy, First, aggregates, joins, etc. all work directly on collections. Enumeration snapshots the data, so you can safely modify a collection while iterating a query over it.
• Full CRUD — Insert, InsertRange, Update, Upsert, Delete, DeleteMany, DeleteAll, FindById.
• Indexes — EnsureIndex(x => x.Email, unique: true) builds an in-memory hash index; Find(x => x.Email, "a@b.c") then resolves in O(1) instead of scanning. Unique indexes reject duplicate keys on insert and update (multiple nulls allowed). Indexes are rebuilt on open — call EnsureIndex once after opening.
• Two storage modes — the default Snapshot mode rewrites a collection's file on each flush; StorageMode = LoddeStorageMode.AppendOnly appends one encrypted record per mutation instead, so writes cost O(change) — better for large collections. The log replays on load, survives crash-truncated tails, and compacts automatically (past CompactionThreshold and on dispose). Files convert between modes transparently.
• Automatic ids — documents expose an Id (or <TypeName>Id) property of int, long, Guid, or string; integer ids auto-increment and Guid ids are generated on insert.
• Encrypted binary storage — data is serialized and encrypted with AES-256-GCM. Keys are derived from your password with PBKDF2-SHA256 (210k iterations by default); every file carries a random salt and every write uses a fresh nonce. A wrong password fails authentication cleanly with LoddeInvalidPasswordException — plaintext and even property names never touch disk.
• Crash-safe writes — files are written to a temp file and atomically moved into place, so a crash mid-write cannot corrupt existing data.
• Flush control — AutoFlush (default on) persists after every mutation; turn it off for batch work and call Flush() or dispose the database to persist.
• Thread-safe — collection operations are internally synchronized.

Usage

using LODDE;

public class User
{
    public int Id { get; set; }          // auto-incremented on insert
    public string Name { get; set; } = "";
    public bool IsAdmin { get; set; }
}

using var db = new LoddeDatabase(new LoddeOptions
{
    DataDirectory = "app-data",
    Password = "s3cret",
});

var users = db.GetCollection<User>();
users.Insert(new User { Name = "Ada", IsAdmin = true });

var admins = users.Where(u => u.IsAdmin).OrderBy(u => u.Name).ToList();

Project layout

• src/LODDE — the class library
• tests/LODDE.Tests — xUnit test suite (dotnet test)