diff --git a/Orm/Xtensive.Orm.Tests/Issues/IssueJira0797_InOverPersistentInterface.cs b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0797_InOverPersistentInterface.cs
new file mode 100644
index 0000000000..6c2816ca34
--- /dev/null
+++ b/Orm/Xtensive.Orm.Tests/Issues/IssueJira0797_InOverPersistentInterface.cs
@@ -0,0 +1,274 @@
+// Copyright (C) 2026 Xtensive LLC.
+// This code is distributed under MIT license terms.
+// See the License.txt file in the project root for more information.
+
+using System;
+using System.Linq;
+using NUnit.Framework;
+using Xtensive.Orm.Configuration;
+using Xtensive.Orm.Tests.Issues.IssueJira0797_InOverPersistentInterfaceModel;
+
+namespace Xtensive.Orm.Tests.Issues.IssueJira0797_InOverPersistentInterfaceModel
+{
+  public interface IPersistentObject
+  {
+    [Field, Key]
+    long Id { get; }
+
+    [Field, Version]
+    int VersionId { get; }
+  }
+
+  public abstract class PersistentObject : Entity, IPersistentObject
+  {
+    public long Id { get; private set; }
+
+    public int VersionId { get; private set; }
+
+    public PersistentObject(Session session)
+      : base(session)
+    {
+    }
+  }
+
+  public interface IHasReasons : IEntity, IPersistentObject
+  {
+    IHasReasons ReasonParent { get; }
+
+    [Field(Length = 150)]
+    string Name { get; }
+
+    [Field]
+    [Association(OnOwnerRemove = OnRemoveAction.Cascade, OnTargetRemove = OnRemoveAction.Clear, PairTo = nameof(ImplemetorDependant.Owner))]
+    EntitySet<ImplemetorDependant> Items { get; }
+  }
+
+  [HierarchyRoot]
+  public class RootImplementor1 : PersistentObject, IHasReasons
+  {
+    [Field]
+    public IHasReasons ReasonParent { get; set; }
+
+    [Field(Length = 150)]
+    public string Name { get; private set; }
+
+    [Field]
+    public EntitySet<ImplemetorDependant> Items { get; private set; }
+
+    public RootImplementor1(Session session, string name)
+      : base(session)
+    {
+      Name = name;
+      ReasonParent = null;
+    }
+  }
+
+  [HierarchyRoot]
+  public class HierarchicalImplementor2 : PersistentObject, IHasReasons
+  {
+    [Field]
+    public IHasReasons ReasonParent { get; private set; }
+
+    [Field(Length = 150)]
+    public string Name { get; set; }
+
+    [Field]
+    public EntitySet<ImplemetorDependant> Items { get; private set; }
+
+    public HierarchicalImplementor2(Session session, string name, IHasReasons parent)
+      : base(session)
+    {
+      Name = name;
+      ReasonParent = parent;
+    }
+  }
+
+  [HierarchyRoot]
+  public class ImplemetorDependant : PersistentObject
+  {
+    [Field(Length = 150)]
+    public string Reason { get; set; }
+
+    [Field(Length = 500)]
+    public string Description { get; set; }
+
+    [Field]
+    public IHasReasons Owner { get; set; }
+
+    public ImplemetorDependant(Session session, string reason, string description)
+      : base(session)
+    {
+      Reason = reason;
+      Description = description;
+    }
+  }
+}
+
+namespace Xtensive.Orm.Tests.Issues
+{
+  public sealed class IssueJira0797_InOverPersistentInterface : AutoBuildTest
+  {
+    protected override DomainConfiguration BuildConfiguration()
+    {
+      var config = base.BuildConfiguration();
+      config.Types.Register(typeof(IPersistentObject));
+      config.Types.Register(typeof(PersistentObject));
+      config.Types.Register(typeof(ImplemetorDependant));
+      config.Types.Register(typeof(RootImplementor1));
+      config.Types.Register(typeof(HierarchicalImplementor2));
+      return config;
+    }
+
+    protected override void PopulateData()
+    {
+      using (var session = Domain.OpenSession())
+      using (var tx = session.OpenTransaction()) {
+        var enterprise1 = new RootImplementor1(session, "enterprise1");
+        var site1 = new HierarchicalImplementor2(session, "site1", enterprise1);
+        var site2 = new HierarchicalImplementor2(session, "site2", enterprise1);
+
+        var reason1 = new ImplemetorDependant(session, $"reason1 {enterprise1.Name}", $"{enterprise1.Name} reason1 reason1") { Owner = enterprise1 };
+        var reason2 = new ImplemetorDependant(session, $"reason2 {enterprise1.Name}", $"{enterprise1.Name} reason2 reason2") { Owner = enterprise1 };
+
+        var reason3 = new ImplemetorDependant(session, $"reason1 {site1.Name}", $"{site1.Name} reason1 reason1") { Owner = site1 };
+        var reason4 = new ImplemetorDependant(session, $"reason2 {site1.Name}", $"{site1.Name} reason2 reason2") { Owner = site1 };
+
+        var reason5 = new ImplemetorDependant(session, $"reason1 {site2.Name}", $"{site2.Name} reason1 reason1") { Owner = site2 };
+        var reason6 = new ImplemetorDependant(session, $"reason2 {site2.Name}", $"{site2.Name} reason2 reason2") { Owner = site2 };
+
+        var enterprise2 = new RootImplementor1(session, "enterprise2");
+        var site3 = new HierarchicalImplementor2(session, "anothersite1", enterprise2);
+        var site4 = new HierarchicalImplementor2(session, "anothersite2", enterprise2);
+
+        reason1 = new ImplemetorDependant(session, $"reason1 {enterprise2.Name}", $"{enterprise2.Name} reason1 reason1") { Owner = enterprise2 };
+        reason2 = new ImplemetorDependant(session, $"reason2 {enterprise2.Name}", $"{enterprise2.Name} reason2 reason2") { Owner = enterprise2 };
+
+        reason3 = new ImplemetorDependant(session, $"reason1 {site3.Name}", $"{site3.Name} reason1 reason1") { Owner = site3 };
+        reason4 = new ImplemetorDependant(session, $"reason2 {site3.Name}", $"{site3.Name} reason2 reason2") { Owner = site3 };
+
+        reason5 = new ImplemetorDependant(session, $"reason1 {site4.Name}", $"{site4.Name} reason1 reason1") { Owner = site4 };
+        reason6 = new ImplemetorDependant(session, $"reason2 {site4.Name}", $"{site4.Name} reason2 reason2") { Owner = site4 };
+
+        tx.Complete();
+      }
+    }
+
+    [Test]
+    public void InPersistentInterfaceComplexConditionTest()
+    {
+      using (var session = Domain.OpenSession())
+      using (var tx = session.OpenTransaction()) {
+        var enterprise = session.Query.All<RootImplementor1>().FirstOrDefault(e => e.Name == "enterprise1");
+        var site = session.Query.All<HierarchicalImplementor2>().FirstOrDefault(s => s.Name == "anothersite2");
+        var filter = new IHasReasons[] { enterprise, site };
+        var reaons = session.Query.All<ImplemetorDependant>().Where(l => l.Owner.In(IncludeAlgorithm.ComplexCondition, filter)).ToArray();
+
+        foreach (var reason in reaons) {
+          Assert.That(reason.Owner, Is.EqualTo(enterprise).Or.EqualTo(site));
+        }
+      }
+    }
+
+    [Test]
+    public void IsExectImplementationComplexConditionTest()
+    {
+      using (var session = Domain.OpenSession())
+      using (var tx = session.OpenTransaction()) {
+        var enterprise = session.Query.All<RootImplementor1>().FirstOrDefault(e => e.Name == "enterprise1");
+        var filter1 = new RootImplementor1[] { enterprise };
+        var reasons = session.Query.All<ImplemetorDependant>().Where(l => l.Owner.In(IncludeAlgorithm.ComplexCondition, filter1)).ToArray();
+
+        foreach (var reason in reasons) {
+          Assert.That(reason.Owner, Is.EqualTo(enterprise));
+        }
+
+        var site = session.Query.All<HierarchicalImplementor2>().FirstOrDefault(e => e.Name == "anothersite2");
+        var filter2 = new HierarchicalImplementor2[] { site };
+        reasons = session.Query.All<ImplemetorDependant>().Where(l => l.Owner.In(IncludeAlgorithm.ComplexCondition, filter2)).ToArray();
+
+        foreach (var reason in reasons) {
+          Assert.That(reason.Owner, Is.EqualTo(site));
+        }
+      }
+    }
+
+    [Test]
+    public void InPersistentInterfaceTempTableTest()
+    {
+      using (var session = Domain.OpenSession())
+      using (var tx = session.OpenTransaction()) {
+        var enterprise = session.Query.All<RootImplementor1>().FirstOrDefault(e => e.Name == "enterprise1");
+        var site = session.Query.All<HierarchicalImplementor2>().FirstOrDefault(s => s.Name == "anothersite2");
+        var filter = new IHasReasons[] { enterprise, site };
+        var reaons = session.Query.All<ImplemetorDependant>().Where(l => l.Owner.In(IncludeAlgorithm.TemporaryTable, filter)).ToArray();
+
+        foreach (var reason in reaons) {
+          Assert.That(reason.Owner, Is.EqualTo(enterprise).Or.EqualTo(site));
+        }
+      }
+    }
+
+    [Test]
+    public void InExectImplementationTempTableTest()
+    {
+      using (var session = Domain.OpenSession())
+      using (var tx = session.OpenTransaction()) {
+        var enterprise = session.Query.All<RootImplementor1>().FirstOrDefault(e => e.Name == "enterprise1");
+        var filter1 = new RootImplementor1[] { enterprise };
+        var reasons = session.Query.All<ImplemetorDependant>().Where(l => l.Owner.In(IncludeAlgorithm.TemporaryTable, filter1)).ToArray();
+
+        foreach (var reason in reasons) {
+          Assert.That(reason.Owner, Is.EqualTo(enterprise));
+        }
+
+        var site = session.Query.All<HierarchicalImplementor2>().FirstOrDefault(e => e.Name == "anothersite2");
+        var filter2 = new HierarchicalImplementor2[] { site };
+        reasons = session.Query.All<ImplemetorDependant>().Where(l => l.Owner.In(IncludeAlgorithm.TemporaryTable, filter2)).ToArray();
+
+        foreach (var reason in reasons) {
+          Assert.That(reason.Owner, Is.EqualTo(site));
+        }
+      }
+    }
+
+    [Test]
+    public void ContainsPersistentInterfaceComplexConditionTest()
+    {
+      using (var session = Domain.OpenSession())
+      using (var tx = session.OpenTransaction()) {
+        var enterprise = session.Query.All<RootImplementor1>().FirstOrDefault(e => e.Name == "enterprise1");
+        var site = session.Query.All<HierarchicalImplementor2>().FirstOrDefault(s => s.Name == "anothersite2");
+        var filter = new IHasReasons[] { enterprise, site };
+        var reaons = session.Query.All<ImplemetorDependant>().Where(l => filter.Contains(l.Owner)).ToArray();
+
+        foreach (var reason in reaons) {
+          Assert.That(reason.Owner, Is.EqualTo(enterprise).Or.EqualTo(site));
+        }
+      }
+    }
+
+    [Test]
+    public void ContainsExectImplementationComplexConditionTest()
+    {
+      using (var session = Domain.OpenSession())
+      using (var tx = session.OpenTransaction()) {
+        var enterprise = session.Query.All<RootImplementor1>().FirstOrDefault(e => e.Name == "enterprise1");
+        var filter1 = new RootImplementor1[] { enterprise };
+        var reasons = session.Query.All<ImplemetorDependant>().Where(l => filter1.Contains(l.Owner)).ToArray();
+
+        foreach (var reason in reasons) {
+          Assert.That(reason.Owner, Is.EqualTo(enterprise));
+        }
+
+        var site = session.Query.All<HierarchicalImplementor2>().FirstOrDefault(e => e.Name == "anothersite2");
+        var filter2 = new HierarchicalImplementor2[] { site };
+        reasons = session.Query.All<ImplemetorDependant>().Where(l => filter2.Contains(l.Owner)).ToArray();
+
+        foreach (var reason in reasons) {
+          Assert.That(reason.Owner, Is.EqualTo(site));
+        }
+      }
+    }
+  }
+}
+
diff --git a/Orm/Xtensive.Orm/Orm/Linq/ItemToTupleConverter{TItem}.cs b/Orm/Xtensive.Orm/Orm/Linq/ItemToTupleConverter{TItem}.cs
index 96117f4df2..910d597fb8 100644
--- a/Orm/Xtensive.Orm/Orm/Linq/ItemToTupleConverter{TItem}.cs
+++ b/Orm/Xtensive.Orm/Orm/Linq/ItemToTupleConverter{TItem}.cs
@@ -41,7 +41,7 @@ private class TupleTypeCollection: IReadOnlyCollection<Type>
       public void Add(Type type)
       {
         count++;
-        types = types==null ? EnumerableUtils.One(type) : types.Concat(EnumerableUtils.One(type));
+        types = types == null ? Enumerable.Repeat(type, 1) : types.Append(type);
       }
 
       public void AddRange(IReadOnlyCollection<Type> newTypes)
@@ -74,7 +74,7 @@ private bool IsPersistableType(Type type)
         || type.IsSubclassOf(typeof (Entity))
           || type==typeof (Structure)
             || type.IsSubclassOf(typeof (Structure))
-        ) {
+              || (type.IsInterface && typeof(IEntity).IsAssignableFrom(type))) {
         if (!model.Types.Contains(type))
           throw new InvalidOperationException(String.Format(Strings.ExTypeNotFoundInModel, type.FullName));
         return true;
@@ -198,7 +198,7 @@ private IMappedExpression BuildField(Type type, ref int index, TupleTypeCollecti
 //        return Expression.Convert(entityExpression, type);
 //      }
 
-      if (type.IsSubclassOf(typeof (Entity))) {
+      if (type.IsSubclassOf(typeof (Entity)) || (type.IsInterface && typeof(IEntity).IsAssignableFrom(type)) ) {
         TypeInfo typeInfo = model.Types[type];
         KeyInfo keyInfo = typeInfo.Key;
         TupleDescriptor keyTupleDescriptor = keyInfo.TupleDescriptor;