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ServiceStack.OrmLite is a convention-based, configuration-free lightweight ORM that uses standard POCO classes and Data Annotation attributes to infer its table schema.


OrmLite is a set of light-weight C# extension methods around System.Data.* interfaces which is designed to persist POCO classes with a minimal amount of intrusion and configuration. Another Orm with similar goals is sqlite-net.

OrmLite was designed with a focus on the core objectives:

  • Map a POCO class 1:1 to an RDBMS table, cleanly by conventions, without any attributes required.
  • Create/Drop DB Table schemas using nothing but POCO class definitions (IOTW a true code-first ORM)
  • Simplicity - typed, wrist friendly API for common data access patterns.
  • High performance - with support for indexes, text blobs, etc.
  • Expressive power and flexibility - with access to IDbCommand and raw SQL
  • Cross platform - supports multiple dbs (currently: Sqlite and Sql Server) running on both .NET and Mono platforms.

In OrmLite: 1 Class = 1 Table. There's no hidden behaviour behind the scenes auto-magically managing hidden references to other tables. Any non-scalar properties (i.e. complex types) are text blobbed in a schema-less text field using .NET's fastest Text Serializer. Effectively this allows you to create a table from any POCO type and it should persist as expected in a DB Table with columns for each of the classes 1st level public properties.

Other notable Micro ORMs for .NET

Many performance problems can be mitigated and a lot of use-cases can be simplified without the use of a heavyweight ORM, and their config, mappings and infrastructure. As performance is the most important feature we can recommend the following list, each with their own unique special blend of features.

  • Dapper - by @samsaffron and @marcgravell
    • The current performance king, supports both POCO and dynamic access, fits in a single class. Put in production to solve StackOverflow's DB Perf issues. Requires .NET 4.
  • PetaPoco - by @toptensoftware
    • Fast, supports dynamics, expandos and typed POCOs, fits in a single class, runs on .NET 3.5 and Mono. Includes optional T4 templates for POCO table generation.
  • Massive - by @robconery
    • Fast, supports dynamics and expandos, smart use of optional params to provide a wrist-friendly api, fits in a single class. Multiple RDBMS support. Requires .NET 4.
  • Simple.Data - by @markrendle
    • A little slower than above ORMS, most wrist-friendly courtesy of a dynamic API, multiple RDBMS support inc. Mongo DB. Requires .NET 4.


Download on NuGet

5 flavours of OrmLite is on NuGet: Sql Server, MySql, Firebird, Sqlite32 and Sqlite64.

OrmLite is also included in ServiceStack or available to download separately in /downloads.

Code-first Customer & Order example with complex types on POCO as text blobs

Below is a complete stand-alone example. No other config or classes is required for it to run. It's also available as a stand-alone unit test.

    public enum PhoneType {

    public enum AddressType {

    public class Address {
        public string Line1 { get; set; }
        public string Line2 { get; set; }
        public string ZipCode { get; set; }
        public string State { get; set; }
        public string City { get; set; }
        public string Country { get; set; }

    public class Customer {
        public Customer() {
            this.PhoneNumbers = new Dictionary<PhoneType, string>();
            this.Addresses = new Dictionary<AddressType, Address>();

        [AutoIncrement] // Creates Auto primary key
        public int Id { get; set; }

        public string FirstName { get; set; }
        public string LastName { get; set; }

        [Index(Unique = true)] // Creates Unique Index
        public string Email { get; set; }

        public Dictionary<PhoneType, string> PhoneNumbers { get; private set; }  //Blobbed
        public Dictionary<AddressType, Address> Addresses { get; private set; }  //Blobbed
        public DateTime CreatedAt { get; set; }

    public class Order {

        public int Id { get; set; }

        [References(typeof(Customer))]      //Creates Foreign Key
        public int CustomerId { get; set; }

        [References(typeof(Employee))]      //Creates Foreign Key
        public int EmployeeId { get; set; }

        public Address ShippingAddress { get; set; } //Blobbed (no Address table)

        public DateTime? OrderDate { get; set; }
        public DateTime? RequiredDate { get; set; }
        public DateTime? ShippedDate { get; set; }
        public int? ShipVia { get; set; }
        public decimal Freight { get; set; }
        public decimal Total { get; set; }

    public class OrderDetail {

        public int Id { get; set; }

        [References(typeof(Order))] //Creates Foreign Key
        public int OrderId { get; set; }

        public int ProductId { get; set; }
        public decimal UnitPrice { get; set; }
        public short Quantity { get; set; }
        public decimal Discount { get; set; }

    public class Employee {
        public int Id { get; set; }
        public string Name { get; set; }

    public class Product {
        public int Id { get; set; }
        public string Name { get; set; }
        public decimal UnitPrice { get; set; }

    //Setup SQL Server Connection Factory
    var dbFactory = new OrmLiteConnectionFactory(
        @"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\App_Data\Database1.mdf;Integrated Security=True;User Instance=True",

    //Use in-memory Sqlite DB instead
    //var dbFactory = new OrmLiteConnectionFactory(
    //    ":memory:", false, SqliteOrmLiteDialectProvider.Instance);

    //Non-intrusive: All extension methods hang off System.Data.* interfaces
    IDbConnection dbConn = dbFactory.OpenDbConnection();
    IDbCommand dbCmd = dbConn.CreateCommand();

    //Re-Create all table schemas:


    dbCmd.Insert(new Employee { Id = 1, Name = "Employee 1" });
    dbCmd.Insert(new Employee { Id = 2, Name = "Employee 2" });
    var product1 = new Product { Id = 1, Name = "Product 1", UnitPrice = 10 };
    var product2 = new Product { Id = 2, Name = "Product 2", UnitPrice = 20 };
    dbCmd.Save(product1, product2);

    var customer = new Customer
        FirstName = "Orm",
        LastName = "Lite",
        Email = "",
        PhoneNumbers =
                { PhoneType.Home, "555-1234" },
                { PhoneType.Work, "1-800-1234" },
                { PhoneType.Mobile, "818-123-4567" },
        Addresses =
                { AddressType.Work, new Address { Line1 = "1 Street", Country = "US", State = "NY", City = "New York", ZipCode = "10101" } },
        CreatedAt = DateTime.UtcNow,

    var customerId = dbCmd.GetLastInsertId(); //Get Auto Inserted Id
    customer = dbCmd.QuerySingle<Customer>(new { customer.Email }); //Query
    Assert.That(customer.Id, Is.EqualTo(customerId));

    //Direct access to System.Data.Transactions:
    using (var trans = dbCmd.BeginTransaction(IsolationLevel.ReadCommitted))
        var order = new Order
            CustomerId = customer.Id,
            EmployeeId = 1,
            OrderDate = DateTime.UtcNow,
            Freight = 10.50m,
            ShippingAddress = new Address { Line1 = "3 Street", Country = "US", State = "NY", City = "New York", ZipCode = "12121" },
        dbCmd.Save(order); //Inserts 1st time

        order.Id = (int)dbCmd.GetLastInsertId(); //Get Auto Inserted Id

        var orderDetails = new[] {
            new OrderDetail
                OrderId = order.Id,
                ProductId = product1.Id,
                Quantity = 2,
                UnitPrice = product1.UnitPrice,
            new OrderDetail
                OrderId = order.Id,
                ProductId = product2.Id,
                Quantity = 2,
                UnitPrice = product2.UnitPrice,
                Discount = .15m,


        order.Total = orderDetails.Sum(x => x.UnitPrice * x.Quantity * x.Discount) + order.Freight;

        dbCmd.Save(order); //Updates 2nd Time


Running this against a SQL Server database will yield the results below:

SQL Server Management Studio results

Notice the POCO types are stored in the very fast and Versatile JSV Format which although hard to do - is actually more compact, human and parser-friendly than JSON :)

API Overview

The API is minimal, providing basic shortcuts for the primitive SQL statements:

OrmLite API

Nearly all extension methods hang off the implementation agnostic IDbCommand.

CreateTable<T> and DropTable<T> create and drop tables based on a classes type definition (only public properties used).

For a one-time use of a connection, you can query straight of the IDbFactory with:

var customers = dbFactory.Exec(dbCmd => dbCmd.Where<Customer>(new { Age = 30 }));

The Select methods allow you to construct Sql using C# string.Format() syntax. If you're SQL doesn't start with a SELECT statement, it is assumed a WHERE clause is being provided, e.g:

var tracks = dbCmd.Select<Track>("Artist = {0} AND Album = {1}", "Nirvana", "Heart Shaped Box");

The same results could also be fetched with:

var tracks = dbCmd.Select<Track>("select * from track WHERE Artist = {0} AND Album = {1}", "Nirvana", "Heart Shaped Box");

Select returns multiple records

List<Track> tracks = dbCmd.Select<Track>()

Single returns a single record

Track track = dbCmd.Single<Track>("RefId = {0}", refId)

GetDictionary returns a Dictionary made from the first to columns

Dictionary<int,string> trackIdNamesMap = dbCmd.GetDictionary<int, string>("select Id, Name from Track")

GetLookup returns an Dictionary<K, List<V>> made from the first to columns

    var albumTrackNames = dbCmd.GetLookup<int, string>("select AlbumId, Name from Track")

GetFirstColumn returns a List of first column values

List<string> trackNames = dbCmd.GetFirstColumn<string>("select Name from Track")

GetScalar returns a single scalar value

var trackCount = dbCmd.GetScalar<int>("select count(*) from Track")

All Insert, Update, and Delete methods take multiple params, while InsertAll, UpdateAll and DeleteAll take IEnumerables. GetLastInsertId returns the last inserted records auto incremented primary key.

Save and SaveAll will Insert if no record with Id exists, otherwise it Updates. Both take multiple items, optimized to perform a single read to check for existing records and are executed within a sinlge transaction.

Methods containing the word Each return an IEnumerable and are lazily loaded (i.e. non-buffered).

Selection methods containing the word Query or Where use parameterized SQL (other selection methods do not). Anonymous types passed into Where are treated like an AND filter.

var track3 = dbCmd.Where<Track>(new { AlbumName = "Throwing Copper", TrackNo = 3 })

Query statements take in parameterized SQL using properties from the supplied anonymous type (if any)

var track3 = dbCmd.Query<Track>("select * from Track Where AlbumName = @album and TrackNo = @trackNo", 
    new { album = "Throwing Copper", trackNo = 3 })

GetById(s), QueryById(s), etc provide strong-typed convenience methods to fetch by a Table's Id primary key field.

var track = dbCmd.QueryById<Track>(1);


For simplicity, and to be able to have the same POCO class persisted in db4o, memcached, redis or on the filesystem (i.e. providers included in ServiceStack), each model must have an 'Id' property which is its primary key.

More Examples

In its simplest useage, OrmLite can persist any POCO type without any attributes required:

public class SimpleExample
    public int Id { get; set; }
    public string Name { get; set; }

//Set once before use (i.e. in a static constructor).
OrmLiteConfig.DialectProvider = new SqliteOrmLiteDialectProvider();

using (IDbConnection db = "/path/to/db.sqlite".OpenDbConnection())
using (IDbCommand dbConn = db.CreateCommand())
    dbConn.Insert(new SimpleExample { Id=1, Name="Hello, World!"});
    var rows = dbConn.Select<SimpleExample>();

    Assert.That(rows, Has.Count(1));
    Assert.That(rows[0].Id, Is.EqualTo(1));

To get a better idea of the features of OrmLite lets walk through a complete example using sample tables from the Northwind database. _ (Full source code for this example is available here.) _

So with no other configuration using only the classes below:

public class Shipper
    : IHasId<int>
    public int Id { get; set; }

    [Index(Unique = true)]
    public string CompanyName { get; set; }

    public string Phone { get; set; }

    public int ShipperTypeId { get; set; }

public class ShipperType
    : IHasId<int>
    public int Id { get; set; }

    [Index(Unique = true)]
    public string Name { get; set; }

public class SubsetOfShipper
    public int ShipperId { get; set; }
    public string CompanyName { get; set; }

public class ShipperTypeCount
    public int ShipperTypeId { get; set; }
    public int Total { get; set; }

Creating tables

Creating tables is a simple 1-liner:

using (IDbConnection dbConn = ":memory:".OpenDbConnection())
using (IDbCommand dbCmd = dbConn.CreateCommand())
    const bool overwrite = false;
    dbCmd.CreateTables(overwrite, typeof(Shipper), typeof(ShipperType));

/* In debug mode the line above prints:
  "CompanyName" VARCHAR(40) NOT NULL, 
  "Phone" VARCHAR(24) NULL, 
  "ShipperTypeId" INTEGER NOT NULL, 

  CONSTRAINT "FK_Shippers_ShipperTypes" FOREIGN KEY ("ShipperTypeId") REFERENCES "ShipperTypes" ("ShipperID") 
DEBUG: CREATE UNIQUE INDEX uidx_shippers_companyname ON "Shippers" ("CompanyName" ASC);
  "Name" VARCHAR(40) NOT NULL 
DEBUG: CREATE UNIQUE INDEX uidx_shippertypes_name ON "ShipperTypes" ("Name" ASC);

Transaction Support

As we have direct access to IDbCommand and friends - playing with transactions is easy:

int trainsTypeId, planesTypeId;
using (IDbTransaction dbTrans = dbCmd.BeginTransaction())
    dbCmd.Insert(new ShipperType { Name = "Trains" });
    trainsTypeId = (int) dbCmd.GetLastInsertId();

    dbCmd.Insert(new ShipperType { Name = "Planes" });
    planesTypeId = (int) dbCmd.GetLastInsertId();

using (IDbTransaction dbTrans = dbCmd.BeginTransaction(IsolationLevel.ReadCommitted))
    dbCmd.Insert(new ShipperType { Name = "Automobiles" });
    Assert.That(dbCmd.Select<ShipperType>(), Has.Count(3));

Assert.That(dbCmd.Select<ShipperType>(), Has.Count(2));

CRUD Operations

No ORM is complete without the standard crud operations:

//Performing standard Insert's and Selects
dbCmd.Insert(new Shipper { CompanyName = "Trains R Us", Phone = "555-TRAINS", ShipperTypeId = trainsTypeId });
dbCmd.Insert(new Shipper { CompanyName = "Planes R Us", Phone = "555-PLANES", ShipperTypeId = planesTypeId });
dbCmd.Insert(new Shipper { CompanyName = "We do everything!", Phone = "555-UNICORNS", ShipperTypeId = planesTypeId });

var trainsAreUs = dbCmd.First<Shipper>("ShipperTypeId = {0}", trainsTypeId);
Assert.That(trainsAreUs.CompanyName, Is.EqualTo("Trains R Us"));
Assert.That(dbCmd.Select<Shipper>("CompanyName = {0} OR Phone = {1}", "Trains R Us", "555-UNICORNS"), Has.Count(2));
Assert.That(dbCmd.Select<Shipper>("ShipperTypeId = {0}", planesTypeId), Has.Count(2));

//Lets update a record
trainsAreUs.Phone = "666-TRAINS";
Assert.That(dbCmd.GetById<Shipper>(trainsAreUs.Id).Phone, Is.EqualTo("666-TRAINS"));

//Then make it disappear
Assert.That(dbCmd.GetByIdOrDefault<Shipper>(trainsAreUs.Id), Is.Null);

//And bring it back again

Performing custom queries

And with access to raw sql when you need it - the database is your oyster :)

//Select only a subset from the table
var partialColumns = dbCmd.Select<SubsetOfShipper>(typeof (Shipper), "ShipperTypeId = {0}", planesTypeId);
Assert.That(partialColumns, Has.Count(2));

//Select into another POCO class that matches the sql results
var rows = dbCmd.Select<ShipperTypeCount>(
    "SELECT ShipperTypeId, COUNT(*) AS Total FROM Shippers GROUP BY ShipperTypeId ORDER BY COUNT(*)");

Assert.That(rows, Has.Count(2));
Assert.That(rows[0].ShipperTypeId, Is.EqualTo(trainsTypeId));
Assert.That(rows[0].Total, Is.EqualTo(1));
Assert.That(rows[1].ShipperTypeId, Is.EqualTo(planesTypeId));
Assert.That(rows[1].Total, Is.EqualTo(2));

//And finally lets quickly clean up the mess we've made:

Assert.That(dbCmd.Select<Shipper>(), Has.Count(0));
Assert.That(dbCmd.Select<ShipperType>(), Has.Count(0));
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