LiteDB - .Net, IOS, Android, Windows Phone

LiteDB - .Net, IOS, Android, Windows Phone

참조 URL

1. http://www.litedb.org/
2. https://github.com/mbdavid/litedb
   
3. https://github.com/Ar3sDevelopment/UnitOfWork.NET.LiteDB
   

 

 SQLite와 비슷하게 크로스 플랫폼을 지원하고 있지만 MongoDB에서 영감을 받아 만들어진 LiteDB다. MongoDB와 같이 json 또는 bson 형식으로 데이터를 관리한다.

아래 '코드1'은 "http://www.litedb.org/"에서 나와 있는 코드로 POCO 형식을 입출력하는 예제이며, '코드2'는 POCO 클래스와 실제 물리적인 테이블간의 매칭을 시켜주는 방법을 보여주고 있다.

// Create your POCO class public class Customer { public int Id { get; set; } public string Name { get; set; } public string[] Phones { get; set; } public bool IsActive { get; set; } } // Open database (or create if doesn't exist) using(var db = new LiteDatabase(@"C:\Temp\MyData.db")) { // Get customer collection var col = db.GetCollection<Customer>("customers"); // Create your new customer instance var customer = new Customer { Name = "John Doe", Phones = new string[] { "8000-0000", "9000-0000" }, IsActive = true }; // Insert new customer document (Id will be auto-incremented) col.Insert(customer); // Update a document inside a collection customer.Name = "Joana Doe"; col.Update(customer); // Index document using a document property col.EnsureIndex(x => x.Name); // Use Linq to query documents var results = col.Find(x => x.Name.StartsWith("Jo")); }

[코드1] CRUD

// DbRef to cross references public class Order { public ObjectId Id { get; set; } public DateTime OrderDate { get; set; } public Address ShippingAddress { get; set; } public Customer Customer { get; set; } public List<Product> Products { get; set; } public decimal Total => Products.Sum(p => p.Price); } // Re-use mapper from global instance var mapper = BsonMapper.Global; // "Produts" and "Customer" are from other collections (not embedded document) mapper.Entity<Order>() .DbRef(x => x.Customer, "customers") // 1 to 1/0 reference .DbRef(x => x.Products, "products") // 1 to Many reference .Field(x => x.ShippingAddress, "addr") // Embedded sub document .Index(x => x.OrderDate) // Index this field .Ignore(x => x.Total); // Do not store this using(var db = new LiteDatabase("MyOrderDatafile.db")) { var orders = db.GetCollection<Order>("orders"); // When query Order, includes references var query = orders .Include(x => x.Customer) .Include(x => x.Products) // 1 to many reference .Find(x => x.OrderDate <= DateTime.Now); // Each instance of Order will load Customer/Products references foreach(var order in query) { var name = order.Customer.Name; ... } }

[코드2] Mapping

LiteDB V2 ( 2.0.0 )은 아래와 같은 제한 사항과 기능을 가지고 있다.

제한 사항(Limits) : 

• Collection Name:
  • Pattern: A-Z, _-, 0-9
  • Maxlength of 30 chars
  • Case insensitive
• Index Name:
  • Pattern: A-Z, _-, 0-9 (. for nested document)
  • Maxlength of 30 chars
  • Case sensitive
• BsonDocument Key Name:
  • A-Z, _-, 0-9
  • Case sensitive
• FileStorage FileId:
  • Pattern: same used in file system path/file.
  • Case sensitive
• Collections: 3000 bytes to all collections names
• Documents per collections: UInt.MaxValue
• FileStorage Max File Length: 2Gb per file
• Index key size: 512 bytes after BSON serialization
• BSON document size: 1.044.224 bytes (~1Mb = 256 pages)
• Nested Depth for BSON Documents: 20
• Page Size: 4096 bytes
• DataPage Reserved Bytes: 2039 bytes (like PCT FREE)
• IndexPage Reserved Bytes: 100 bytes (like PCT FREE)
• Database Max Length: In theory, UInt.MaxValue * PageSize (4096) = ~ Too big!

New features in v2 - https://github.com/mbdavid/LiteDB/releases

• Portable version: LiteDB.Core (Supports UWP 8.1/10, Xaramin.iOS and Xaramin.Android)
• Generic data access layer - can use any Stream or you can write your own disk access layer
• Database encription option (using password= in connection string)
• New memory cache manager (do not consume too memory in large inserts/updates)
• Better mapping class from your entity to BsonDocument (like Configurations in EntityFramework)
• Better cross reference with DbRef mapping (see unit tests examples)
• Lazy engine load (open datafile only when run a command)
• Reduce your database size with shrink()
• Support for Initial Size and Limit Size database (connection string)
• Complete re-write engine classes width full debug logger
• Complete stats about data/index usage
• Dump file to Import/Export your data using shell commands
• Full documentation for v2 on Wiki
• See more examples in http://www.litedb.org/