--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/HowTo/DataAccess/MultiplePrimaryKey.cs	Thu Mar 27 21:46:09 2014 +0400
@@ -0,0 +1,39 @@
+using System;
+
+using NUnit.Framework;
+
+using BLToolkit.DataAccess;
+using BLToolkit.Mapping;
+
+namespace HowTo.DataAccess
+{
+	[TestFixture]
+	public class MultiplePrimaryKey
+	{
+		[TableName("Person")]
+		public class Person
+		{
+			[MapField("PersonID"), NonUpdatable]
+			public int    ID;
+
+			// These fields are not real primary key of the table.
+			// They are made primary key for demonstration purpose only.
+			//
+			[/*[a]*/PrimaryKey(1)/*[/a]*/] public string FirstName;
+			[/*[a]*/PrimaryKey(2)/*[/a]*/] public string LastName;
+
+			public string MiddleName;
+		}
+
+		[Test]
+		public void Test()
+		{
+			SqlQuery<Person> query = new SqlQuery<Person>();
+
+			Person person = query./*[a]*/SelectByKey("Tester", "Testerson")/*[/a]*/;
+
+			Assert.IsNotNull(person);
+		}
+	}
+}
+