Error when trying to save value to relation field

db/collection.go

@@ -890,6 +890,11 @@ func (c *collection) tryGetFieldKey(key core.PrimaryDataStoreKey, fieldName stri
 func (c *collection) tryGetSchemaFieldID(fieldName string) (uint32, bool) {
 	for _, field := range c.desc.Schema.Fields {
 		if field.Name == fieldName {
+			if field.IsObject() || field.IsObjectArray() {
+				// We do not wish to match navigational properties, only
+				// fields directly on the collection.
+				return uint32(0), false
+			}
 			return uint32(field.ID), true
 		}
 	}

tests/integration/collection/create/one_to_many/simple_test.go

@@ -0,0 +1,47 @@
+// Copyright 2022 Democratized Data Foundation
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package create
+
+import (
+	"context"
+	"testing"
+
+	"github.com/sourcenetwork/defradb/client"
+	testUtils "github.com/sourcenetwork/defradb/tests/integration/collection"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCreateSaveErrorsGivenValueInRelationField(t *testing.T) {
+	doc, err := client.NewDocFromJSON(
+		[]byte(
+			`{
+				"Name": "Painted House",
+				"Author": "ValueDoesntMatter"
+			}`,
+		),
+	)
+	if err != nil {
+		assert.Fail(t, err.Error())
+	}
+
+	test := testUtils.TestCase{
+		CollectionCalls: map[string][]func(client.Collection) error{
+			"book": []func(c client.Collection) error{
+				func(c client.Collection) error {
+					return c.Save(context.Background(), doc)
+				},
+			},
+		},
+		ExpectedError: "The given field does not exist",
+	}
+
+	executeTestCase(t, test)
+}

tests/integration/collection/create/one_to_many/utils.go

@@ -0,0 +1,36 @@
+// Copyright 2022 Democratized Data Foundation
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package create
+
+import (
+	"testing"
+
+	testUtils "github.com/sourcenetwork/defradb/tests/integration/collection"
+)
+
+var schema = (`
+	type book {
+		Name: String
+		Rating: Float
+		Author: author
+	}
+
+	type author {
+		Name: String
+		Age: Int
+		Verified: Boolean
+		Published: [book]
+	}
+`)
+
+func executeTestCase(t *testing.T, test testUtils.TestCase) {
+	testUtils.ExecuteQueryTestCase(t, schema, test)
+}