Add support for DELETE table joins

Author: mythz

src/ServiceStack.OrmLite.SqlServer/SqlServerExpression.cs

@@ -53,6 +53,13 @@ protected override void VisitFilter(string operand, object originalLeft, object
                 right = "CAST({0} AS TIME)".Fmt(right);
             }
         }
+
+        public override string ToDeleteRowStatement()
+        {
+            return base.tableDefs.Count > 1
+                ? $"DELETE {DialectProvider.GetQuotedTableName(modelDef)} {FromExpression} {WhereExpression}"
+                : base.ToDeleteRowStatement();
+        }
     }
 
     internal class SqlServerExpressionUtils

src/ServiceStack.OrmLite/Expressions/SqlExpression.cs

@@ -990,6 +990,16 @@ public virtual void CopyParamsTo(IDbCommand dbCmd)
 
         public virtual string ToDeleteRowStatement()
         {
+            var hasTableJoin = tableDefs.Count > 1;
+            if (hasTableJoin)
+            {
+                var clone = this.Clone();
+                var pk = DialectProvider.GetQuotedColumnName(modelDef, modelDef.PrimaryKey);
+                clone.Select(pk);
+                var subSql = clone.ToSelectStatement();
+                var sql = $"DELETE FROM {DialectProvider.GetQuotedTableName(modelDef)} WHERE {pk} IN ({subSql})";
+                return sql;
+            }
             return $"DELETE FROM {DialectProvider.GetQuotedTableName(modelDef)} {WhereExpression}";
         }
 

tests/ServiceStack.OrmLite.Tests/Expression/SqlExpressionDeleteTests.cs

@@ -0,0 +1,43 @@
+using NUnit.Framework;
+using ServiceStack.OrmLite.Tests.Shared;
+
+namespace ServiceStack.OrmLite.Tests.Expression
+{
+    class PersonJoin
+    {
+        public int Id { get; set; }
+        public int PersonId { get; set; }
+    }
+
+    [TestFixture]
+    public class SqlExpressionDeleteTests : OrmLiteTestBase
+    {
+        [Test]
+        public void Can_delete_entity_with_join_expression()
+        {
+            if (Dialect == Dialect.MySql) return; //Not Supported
+
+            using (var db = OpenDbConnection())
+            {
+                db.DropAndCreateTable<Person>();
+                db.DropAndCreateTable<PersonJoin>();
+
+                db.Insert(new Person { Id = 1, FirstName = "Foo" });
+                db.Insert(new PersonJoin { Id = 1, PersonId = 1 });
+                db.Insert(new PersonJoin { Id = 2, PersonId = 1 });
+
+                var q = db.From<Person>()
+                    .Join<PersonJoin>((x, y) => x.Id == y.PersonId)
+                    .Where<PersonJoin>(x => x.Id == 2);
+
+                var record = db.Single(q);
+
+                Assert.That(record.Id, Is.EqualTo(1));
+
+                db.Delete(q);
+
+                Assert.That(db.Select<Person>().Count, Is.EqualTo(0));
+            }
+        }
+    }
+}

tests/ServiceStack.OrmLite.Tests/ServiceStack.OrmLite.Tests.csproj

@@ -140,6 +140,7 @@
     <Compile Include="Async\SqlExpressionTests.cs" />
     <Compile Include="Async\SqlServerProviderTestsAsync.cs" />
     <Compile Include="Async\UpdateAsyncTests.cs" />
+    <Compile Include="Expression\SqlExpressionDeleteTests.cs" />
     <Compile Include="Expression\SqlExpressionJoinTests.cs" />
     <Compile Include="Issues\JoinAliasWithSchemaIssue.cs" />
     <Compile Include="Issues\LoadReferencesNullReferenceIssue.cs" />