diff --git a/vendor/github.com/opencord/voltha-go/db/model/child_type.go b/vendor/github.com/opencord/voltha-go/db/model/child_type.go
new file mode 100644
index 0000000..da6f688
--- /dev/null
+++ b/vendor/github.com/opencord/voltha-go/db/model/child_type.go
@@ -0,0 +1,136 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ * http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package model
+
+import (
+	desc "github.com/golang/protobuf/descriptor"
+	"github.com/golang/protobuf/proto"
+	"github.com/golang/protobuf/protoc-gen-go/descriptor"
+	"github.com/opencord/voltha-go/common/log"
+	"github.com/opencord/voltha-protos/go/common"
+	"reflect"
+	"strconv"
+	"sync"
+)
+
+type singletonChildTypeCache struct {
+	Cache map[interface{}]map[string]*ChildType
+}
+
+var instanceChildTypeCache *singletonChildTypeCache
+var onceChildTypeCache sync.Once
+
+func getChildTypeCache() *singletonChildTypeCache {
+	onceChildTypeCache.Do(func() {
+		instanceChildTypeCache = &singletonChildTypeCache{}
+	})
+	return instanceChildTypeCache
+}
+
+// ChildType structure contains construct details of an object
+type ChildType struct {
+	ClassModule string
+	ClassType   reflect.Type
+	IsContainer bool
+	Key         string
+	KeyFromStr  func(s string) interface{}
+}
+
+// ChildrenFields retrieves list of child objects associated to a given interface
+func ChildrenFields(cls interface{}) map[string]*ChildType {
+	if cls == nil {
+		return nil
+	}
+	var names map[string]*ChildType
+	var namesExist bool
+
+	if getChildTypeCache().Cache == nil {
+		getChildTypeCache().Cache = make(map[interface{}]map[string]*ChildType)
+	}
+
+	msgType := reflect.TypeOf(cls)
+	inst := getChildTypeCache()
+
+	if names, namesExist = inst.Cache[msgType.String()]; !namesExist {
+		names = make(map[string]*ChildType)
+
+		_, md := desc.ForMessage(cls.(desc.Message))
+
+		// TODO: Do we need to validate MD for nil, panic or exception?
+		for _, field := range md.Field {
+			if options := field.GetOptions(); options != nil {
+				if proto.HasExtension(options, common.E_ChildNode) {
+					isContainer := *field.Label == descriptor.FieldDescriptorProto_LABEL_REPEATED
+					meta, _ := proto.GetExtension(options, common.E_ChildNode)
+
+					var keyFromStr func(string) interface{}
+					var ct ChildType
+
+					parentType := FindOwnerType(reflect.ValueOf(cls), field.GetName(), 0, false)
+					if meta.(*common.ChildNode).GetKey() != "" {
+						keyType := FindKeyOwner(reflect.New(parentType).Elem().Interface(), meta.(*common.ChildNode).GetKey(), 0)
+
+						switch keyType.(reflect.Type).Name() {
+						case "string":
+							keyFromStr = func(s string) interface{} {
+								return s
+							}
+						case "int32":
+							keyFromStr = func(s string) interface{} {
+								i, _ := strconv.Atoi(s)
+								return int32(i)
+							}
+						case "int64":
+							keyFromStr = func(s string) interface{} {
+								i, _ := strconv.Atoi(s)
+								return int64(i)
+							}
+						case "uint32":
+							keyFromStr = func(s string) interface{} {
+								i, _ := strconv.Atoi(s)
+								return uint32(i)
+							}
+						case "uint64":
+							keyFromStr = func(s string) interface{} {
+								i, _ := strconv.Atoi(s)
+								return uint64(i)
+							}
+						default:
+							log.Errorf("Key type not implemented - type: %s\n", keyType.(reflect.Type))
+						}
+					}
+
+					ct = ChildType{
+						ClassModule: parentType.String(),
+						ClassType:   parentType,
+						IsContainer: isContainer,
+						Key:         meta.(*common.ChildNode).GetKey(),
+						KeyFromStr:  keyFromStr,
+					}
+
+					names[field.GetName()] = &ct
+				}
+			}
+		}
+
+		getChildTypeCache().Cache[msgType.String()] = names
+	} else {
+		log.Debugf("Cache entry for %s: %+v", msgType.String(), inst.Cache[msgType.String()])
+	}
+
+	return names
+}