Join the new google group or follow @demisbellot and @ServiceStack for twitter updates.

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

ServiceStack.OrmLite is an independent library and can be used with or without the ServiceStack webservices framework.

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 by Frank Krueger.

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.
  • Amongst the fastest Micro ORMs for .NET (just behind Dapper).
• Expressive power and flexibility - with access to IDbCommand and raw SQL
• Cross platform - supports multiple dbs (currently: Sql Server, Sqlite, MySql, PostgreSQL, Firebird) 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.

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

We've now added SQL Expression support to bring you even nicer LINQ-liked querying to all our providers. To give you a flavour here are some examples with their partial SQL output (done in SQL Server):

int agesAgo = DateTime.Today.AddYears(-20).Year;
db.Select<Author>(q => q.Birthday >= new DateTime(agesAgo, 1, 1) && q.Birthday <= new DateTime(agesAgo, 12, 31));

WHERE (("Birthday" >= '1992-01-01 00:00:00.000') AND ("Birthday" <= '1992-12-31 00:00:00.000'))

db.Select<Author>(q => Sql.In(q.City, "London", "Madrid", "Berlin"));

WHERE "JobCity" In ('London', 'Madrid', 'Berlin')

db.Select<Author>(q => q.Earnings <= 50);

WHERE ("Earnings" <= 50)

db.Select<Author>(q => q.Name.StartsWith("A"));

WHERE upper("Name") like 'A%'

db.Select<Author>(q => q.Name.EndsWith("garzon"));

WHERE upper("Name") like '%GARZON'

db.Select<Author>(q => q.Name.Contains("Benedict"));

WHERE upper("Name") like '%BENEDICT%'

db.Select<Author>(q => q.Rate == 10 && q.City == "Mexico");

WHERE (("Rate" = 10) AND ("JobCity" = 'Mexico'))

Right now the Expression support can satisfy most simple queries with a strong-typed API. For anything more complex (e.g. queries with table joins) you can still easily fall back to raw SQL queries as seen below.

To see the behaviour of the different APIs, all examples uses this simple model

public class Person
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public int? Age { get; set; }
}

In its most simple form, updating any model without any filters will update every field, except the Id which is used to filter the update to this specific record:

db.Update(new Person { Id = 1, FirstName = "Jimi", LastName = "Hendrix", Age = 27});

UPDATE "Person" SET "FirstName" = 'Jimi',"LastName" = 'Hendrix',"Age" = 27 WHERE "Id" = 1

If you supply your own where expression, it updates every field (inc. Id) but uses your filter instead:

db.Update(new Person { Id = 1, FirstName = "JJ" }, p => p.LastName == "Hendrix");

UPDATE "Person" SET "Id" = 1,"FirstName" = 'JJ',"LastName" = NULL,"Age" = NULL WHERE ("LastName" = 'Hendrix')

One way to limit the fields which gets updated is to use an Anonymous Type:

db.Update<Person>(new { FirstName = "JJ" }, p => p.LastName == "Hendrix");

Or by using UpdateNonDefaults which only updates the non-default values in your model using the filter specified:

db.UpdateNonDefaults(new Person { FirstName = "JJ" }, p => p.LastName == "Hendrix");

UPDATE "Person" SET "FirstName" = 'JJ' WHERE ("LastName" = 'Hendrix')

As updating a partial row is a common use-case in Db's, we've added a number of methods for just this purpose, named UpdateOnly.

The first expression in an UpdateOnly statement is used to specify which fields should be updated:

db.UpdateOnly(new Person { FirstName = "JJ" }, p => p.FirstName);

UPDATE "Person" SET "FirstName" = 'JJ'

When present, the second expression is used as the where filter:

db.UpdateOnly(new Person { FirstName = "JJ" }, p => p.FirstName, p => p.LastName == "Hendrix");

UPDATE "Person" SET "FirstName" = 'JJ' WHERE ("LastName" = 'Hendrix')

Instead of using the expression filters above you can choose to use an ExpressionVisitor builder which provides more flexibility when you want to programatically construct the update statement:

db.UpdateOnly(new Person { FirstName = "JJ", LastName = "Hendo" }, ev => ev.Update(p => p.FirstName));

UPDATE "Person" SET "FirstName" = 'JJ'

db.UpdateOnly(new Person { FirstName = "JJ" }, ev => ev.Update(p => p.FirstName).Where(x => x.FirstName == "Jimi"));

UPDATE "Person" SET "FirstName" = 'JJ' WHERE ("LastName" = 'Hendrix')

For the ultimate flexibility we also provide un-typed, string-based expressions. Use the .Params() extension method escape parameters (inspired by massive):

db.Update<Person>(set: "FirstName = {0}".Params("JJ"), where: "LastName = {0}".Params("Hendrix"));

Even the Table name can be a string so you perform the same update without requiring the Person model at all:

db.Update(table: "Person", set: "FirstName = {0}".Params("JJ"), where: "LastName = {0}".Params("Hendrix"));

UPDATE "Person" SET FirstName = 'JJ' WHERE LastName = 'Hendrix'

Insert's are pretty straight forward since in most cases you want to insert every field:

db.Insert(new Person { Id = 1, FirstName = "Jimi", LastName = "Hendrix", Age = 27 });

INSERT INTO "Person" ("Id","FirstName","LastName","Age") VALUES (1,'Jimi','Hendrix',27)

But do provide an API that takes an Expression Visitor for the rare cases you don't want to insert every field

db.InsertOnly(new Person { FirstName = "Amy" }, ev => ev.Insert(p => new { p.FirstName }));

INSERT INTO "Person" ("FirstName") VALUES ('Amy')

Like updates for DELETE's we also provide APIs that take a where Expression:

db.Delete<Person>(p => p.Age == 27);

Or an Expression Visitor:

db.Delete<Person>(ev => ev.Where(p => p.Age == 27));

DELETE FROM "Person" WHERE ("Age" = 27)

As well as un-typed, string-based expressions:

db.Delete<Person>(where: "Age = {0}".Params(27));

Which also can take a table name so works without requiring a typed Person model

db.Delete(table: "Person", where: "Age = {0}".Params(27));

DELETE FROM "Person" WHERE Age = 27

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 {
        Home,
        Work,
        Mobile,
    }

    public enum AddressType {
        Home,
        Work,
        Other,
    }

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

    public class Order {
        
        [AutoIncrement]
        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 {
        
        [AutoIncrement]
        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",
    	SqlServerOrmLiteDialectProvider.Instance);

    //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 db = dbFactory.OpenDbConnection();

    //Re-Create all table schemas:
    db.DropTable<OrderDetail>();
    db.DropTable<Order>();
    db.DropTable<Customer>();
    db.DropTable<Product>();
    db.DropTable<Employee>();

    db.CreateTable<Employee>();
    db.CreateTable<Product>();
    db.CreateTable<Customer>();
    db.CreateTable<Order>();
    db.CreateTable<OrderDetail>();

    db.Insert(new Employee { Id = 1, Name = "Employee 1" });
    db.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 };
    db.Save(product1, product2);

    var customer = new Customer
    {
        FirstName = "Orm",
        LastName = "Lite",
        Email = "ormlite@servicestack.net",
        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,
    };
    db.Insert(customer);

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

    //Direct access to System.Data.Transactions:
    using (var trans = db.OpenTransaction(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" },
        };
        db.Save(order); //Inserts 1st time

        order.Id = (int)db.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,
            }
        };

        db.Insert(orderDetails);

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

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

        trans.Commit();
    }

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

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 :)

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

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 => db.Where<Customer>(new { Age = 30 }));

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

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

The same results could also be fetched with:

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

Select returns multiple records

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

Single returns a single record

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

GetDictionary returns a Dictionary made from the first to columns

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

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

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

GetFirstColumn returns a List of first column values

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

GetScalar returns a single scalar value

var trackCount = db.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 = db.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 = db.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 = db.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.

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())
{
	db.CreateTable<SimpleExample>(true);
	db.Insert(new SimpleExample { Id=1, Name="Hello, World!"});
	var rows = db.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:

[Alias("Shippers")]
public class Shipper
	: IHasId<int>
{
	[AutoIncrement]
	[Alias("ShipperID")]
	public int Id { get; set; }

	[Required]
	[Index(Unique = true)]
	[StringLength(40)]
	public string CompanyName { get; set; }

	[StringLength(24)]
	public string Phone { get; set; }

	[References(typeof(ShipperType))]
	public int ShipperTypeId { get; set; }
}

[Alias("ShipperTypes")]
public class ShipperType
	: IHasId<int>
{
	[AutoIncrement]
	[Alias("ShipperTypeID")]
	public int Id { get; set; }

	[Required]
	[Index(Unique = true)]
	[StringLength(40)]
	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 is a simple 1-liner:

using (IDbConnection db = ":memory:".OpenDbConnection())
{
	const bool overwrite = false;
	db.CreateTables(overwrite, typeof(Shipper), typeof(ShipperType));
}

/* In debug mode the line above prints:
DEBUG: CREATE TABLE "Shippers" 
(
  "ShipperID" INTEGER PRIMARY KEY AUTOINCREMENT, 
  "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);
DEBUG: CREATE TABLE "ShipperTypes" 
(
  "ShipperTypeID" INTEGER PRIMARY KEY AUTOINCREMENT, 
  "Name" VARCHAR(40) NOT NULL 
);
DEBUG: CREATE UNIQUE INDEX uidx_shippertypes_name ON "ShipperTypes" ("Name" ASC);
*/

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

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

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

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

	dbTrans.Rollback();
}
Assert.That(db.Select<ShipperType>(), Has.Count(2));

No ORM is complete without the standard crud operations:

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

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

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

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

//And bring it back again
db.Insert(trainsAreUs);

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

//Select only a subset from the table
var partialColumns = db.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 = db.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:
db.DeleteAll<Shipper>();
db.DeleteAll<ShipperType>();

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

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.