diff --git a/association.go b/association.go
index c90258ec..4d240418 100644
--- a/association.go
+++ b/association.go
@@ -179,9 +179,9 @@ func (association *Association) Replace(values ...interface{}) error {
 func (association *Association) Delete(values ...interface{}) error {
 	if association.Error == nil {
 		var (
-			tx               = association.DB
+			reflectValue     = association.DB.Statement.ReflectValue
 			rel              = association.Relationship
-			reflectValue     = tx.Statement.ReflectValue
+			tx               = association.DB
 			relFields        []*schema.Field
 			foreignKeyFields []*schema.Field
 			foreignKeys      []string
@@ -201,14 +201,12 @@ func (association *Association) Delete(values ...interface{}) error {
 					foreignKeys = append(foreignKeys, ref.ForeignKey.DBName)
 					updateAttrs[ref.ForeignKey.DBName] = nil
 				}
-			} else {
-				tx.Where(clause.Eq{Column: ref.ForeignKey.DBName, Value: ref.PrimaryKey})
 			}
 		}
 
 		relValuesMap, relQueryValues := schema.GetIdentityFieldValuesMapFromValues(values, relFields)
 		column, values := schema.ToQueryValues(foreignKeys, relQueryValues)
-		tx.Where(clause.IN{Column: column, Values: values})
+		tx = tx.Session(&Session{}).Where(clause.IN{Column: column, Values: values})
 
 		switch rel.Type {
 		case schema.HasOne, schema.HasMany:
@@ -407,7 +405,7 @@ func (association *Association) saveAssociation(clear bool, values ...interface{
 		if clear && len(values) == 0 {
 			association.Relationship.Field.Set(reflectValue, reflect.New(association.Relationship.Field.IndirectFieldType).Interface())
 			for _, ref := range association.Relationship.References {
-				if !ref.OwnPrimaryKey {
+				if !ref.OwnPrimaryKey && ref.PrimaryValue == "" {
 					ref.ForeignKey.Set(reflectValue, reflect.Zero(ref.ForeignKey.FieldType).Interface())
 				}
 			}
diff --git a/tests/associations_test.go b/tests/associations_test.go
index 137b2c50..0b131450 100644
--- a/tests/associations_test.go
+++ b/tests/associations_test.go
@@ -285,7 +285,7 @@ func TestHasOneAssociation(t *testing.T) {
 	AssertAssociationCount(t, user2, "Account", 1, "AfterReplace")
 
 	// Delete
-	if err := DB.Model(&user2).Association("Account").Delete(&Company{}); err != nil {
+	if err := DB.Model(&user2).Association("Account").Delete(&Account{}); err != nil {
 		t.Fatalf("Error happened when delete account, got %v", err)
 	}
 	AssertAssociationCount(t, user2, "Account", 1, "after delete non-existing data")
@@ -309,3 +309,79 @@ func TestHasOneAssociation(t *testing.T) {
 
 	AssertAssociationCount(t, user2, "Account", 0, "after clear")
 }
+
+func TestPolymorphicHasOneAssociation(t *testing.T) {
+	var pet = Pet{Name: "hasone", Toy: Toy{Name: "toy-has-one"}}
+
+	if err := DB.Create(&pet).Error; err != nil {
+		t.Fatalf("errors happened when create: %v", err)
+	}
+
+	CheckPet(t, pet, pet)
+
+	// Find
+	var pet2 Pet
+	DB.Find(&pet2, "id = ?", pet.ID)
+	DB.Model(&pet2).Association("Toy").Find(&pet2.Toy)
+	CheckPet(t, pet2, pet)
+
+	// Count
+	AssertAssociationCount(t, pet, "Toy", 1, "")
+
+	// Append
+	var toy = Toy{Name: "toy-has-one-append"}
+
+	if err := DB.Model(&pet2).Association("Toy").Append(&toy); err != nil {
+		t.Fatalf("Error happened when append toy, got %v", err)
+	}
+
+	if toy.ID == 0 {
+		t.Fatalf("Toy's ID should be created")
+	}
+
+	pet.Toy = toy
+	CheckPet(t, pet2, pet)
+
+	AssertAssociationCount(t, pet, "Toy", 1, "AfterAppend")
+
+	// Replace
+	var toy2 = Toy{Name: "toy-has-one-replace"}
+
+	if err := DB.Model(&pet2).Association("Toy").Replace(&toy2); err != nil {
+		t.Fatalf("Error happened when append Toy, got %v", err)
+	}
+
+	if toy2.ID == 0 {
+		t.Fatalf("toy2's ID should be created")
+	}
+
+	pet.Toy = toy2
+	CheckPet(t, pet2, pet)
+
+	AssertAssociationCount(t, pet2, "Toy", 1, "AfterReplace")
+
+	// Delete
+	if err := DB.Model(&pet2).Association("Toy").Delete(&Toy{}); err != nil {
+		t.Fatalf("Error happened when delete toy, got %v", err)
+	}
+	AssertAssociationCount(t, pet2, "Toy", 1, "after delete non-existing data")
+
+	if err := DB.Model(&pet2).Association("Toy").Delete(&toy2); err != nil {
+		t.Fatalf("Error happened when delete Toy, got %v", err)
+	}
+	AssertAssociationCount(t, pet2, "Toy", 0, "after delete")
+
+	// Prepare Data for Clear
+	if err := DB.Model(&pet2).Association("Toy").Append(&toy); err != nil {
+		t.Fatalf("Error happened when append Toy, got %v", err)
+	}
+
+	AssertAssociationCount(t, pet2, "Toy", 1, "after prepare data")
+
+	// Clear
+	if err := DB.Model(&pet2).Association("Toy").Clear(); err != nil {
+		t.Errorf("Error happened when clear Toy, got %v", err)
+	}
+
+	AssertAssociationCount(t, pet2, "Toy", 0, "after clear")
+}