diff --git a/storage/message/message.go b/storage/message/message.go
index 781f463..204d6e4 100644
--- a/storage/message/message.go
+++ b/storage/message/message.go
@@ -23,7 +23,7 @@ func MakeMessage(c *tracking.Container, h ...string) *tracking.Track {
 }
 
 func (msg *message) Domain() string {
-	return msg.Head["domain"]
+	return msg.Head()["domain"]
 }
 
 // message container
diff --git a/storage/tracking/tracking.go b/storage/tracking/tracking.go
index e1819b5..77ac1a3 100644
--- a/storage/tracking/tracking.go
+++ b/storage/tracking/tracking.go
@@ -26,17 +26,40 @@ type AdapterFactory func(*Track) Adapted
 
 type Track struct {
 	trackId   lib.Ident
-	Head      lib.StrMap
-	TimeStamp *time.Time
-	Data      lib.Map
+	head      lib.StrMap
+	timeStamp *time.Time
+	data      lib.Map
 	container *Container
 	adapter   AdapterFactory
 }
 
+func MakeTrack(cont *Container, h ...string) *Track {
+	tr := Track{
+		head:      lib.StrMap{},
+		data:      lib.Map{},
+		container: cont,
+		adapter:   func(tr *Track) Adapted { return tr },
+	}
+	tr.SetHead(h...)
+	return &tr
+}
+
 func (tr *Track) TrackId() lib.Ident {
 	return tr.trackId
 }
 
+func (tr *Track) Head() lib.StrMap {
+	return tr.head
+}
+
+func (tr *Track) TimeStamp() *time.Time {
+	return tr.timeStamp
+}
+
+func (tr *Track) Data() lib.Map {
+	return tr.data
+}
+
 func (tr *Track) Container() *Container {
 	return tr.container
 }
@@ -45,14 +68,47 @@ func (tr *Track) Uid() string {
 	return fmt.Sprintf("%s-%d", tr.container.Prefix, tr.trackId)
 }
 
-func MakeTrack(cont *Container, h ...string) *Track {
-	tr := Track{
-		Head:      lib.StrMap{},
-		container: cont,
-		adapter:   func(tr *Track) Adapted { return tr },
+func (tr *Track) SetHead(h ...string) {
+	for i, k := range tr.container.HeadFields {
+		if i >= len(h) {
+			break
+		}
+		if h[i] != "" {
+			tr.head[k] = h[i]
+		}
 	}
-	tr.SetHead(h...)
-	return &tr
+}
+
+func (tr *Track) SetTimeStamp(ts *time.Time) {
+	tr.timeStamp = ts
+}
+
+func (tr *Track) SetData(data lib.Map) {
+	tr.data = data
+}
+
+func (tr *Track) ScanP(rows *sql.Rows) error {
+	tr.head = lib.StrMap{}
+	var d []any
+	for range tr.container.HeadFields {
+		var hv string
+		d = append(d, &hv)
+	}
+	var ts, rd string
+	d = append(d, &ts, &rd, &tr.trackId)
+	err := rows.Scan(d...)
+	if err != nil {
+		log.Error(err).Msg("storage.tracking.ScanP: rows.Scan")
+	}
+	for i, k := range tr.container.HeadFields {
+		tr.head[k] = *d[i].(*string)
+	}
+	tr.timeStamp = ParseDateTime(ts)
+	err = json.Unmarshal([]byte(rd), &tr.data)
+	if err != nil {
+		log.Error(err).Msg("storage.tracking.ScanP: json.Unmarshal")
+	}
+	return err
 }
 
 func (tr *Track) SetAdapterFactory(af AdapterFactory) *Track {
@@ -64,38 +120,6 @@ func Adapt[T Adapted](tr *Track) T {
 	return tr.adapter(tr).(T)
 }
 
-func (tr *Track) SetHead(h ...string) {
-	for i, k := range tr.container.HeadFields {
-		if i >= len(h) {
-			break
-		}
-		if h[i] != "" {
-			tr.Head[k] = h[i]
-		}
-	}
-}
-
-func (tr *Track) ScanP(rows *sql.Rows) error {
-	tr.Head = lib.StrMap{}
-	var d []any
-	for range tr.container.HeadFields {
-		var hv string
-		d = append(d, &hv)
-	}
-	var ts, rd string
-	d = append(d, &ts, &rd, &tr.trackId)
-	err := rows.Scan(d...)
-	for i, k := range tr.container.HeadFields {
-		tr.Head[k] = *d[i].(*string)
-	}
-	tr.TimeStamp = ParseDateTime(ts)
-	err = json.Unmarshal([]byte(rd), &tr.Data)
-	if err != nil {
-		log.Error(err).Msg("storage.tracking.ScanP")
-	}
-	return err
-}
-
 // basic container implementation
 
 type ContDef struct {
@@ -214,7 +238,7 @@ func (cont *Container) Query(quSpec *querySpec) []*Track {
 
 func (cont *Container) NewTrack(h []string, data lib.Map) *Track {
 	tr := cont.ItemFactory(cont, h...)
-	tr.Data = data
+	tr.data = data
 	cont.Insert(tr)
 	return tr
 }
@@ -231,14 +255,14 @@ func (cont *Container) Insert(tr *Track) *Track {
 	sql := storage.BuildSql(SqlInsert, quSpec)
 	var values []any
 	for _, k := range cont.HeadFields {
-		values = append(values, tr.Head[k])
+		values = append(values, tr.head[k])
 	}
-	b, _ := json.Marshal(tr.Data)
+	b, _ := json.Marshal(tr.data)
 	values = append(values, b)
 	var tsstr string
 	proc := func(r *sqllib.Rows) error {
 		err := r.Scan(&tr.trackId, &tsstr)
-		tr.TimeStamp = ParseDateTime(tsstr)
+		tr.timeStamp = ParseDateTime(tsstr)
 		return err
 	}
 	if err := cont.Storage.Query(proc, sql, values...); err == nil {
@@ -248,9 +272,9 @@ func (cont *Container) Insert(tr *Track) *Track {
 }
 
 func (cont *Container) Update(tr *Track) *Track {
-	if tr.TimeStamp == nil {
+	if tr.timeStamp == nil {
 		ts := time.Now()
-		tr.TimeStamp = &ts
+		tr.timeStamp = &ts
 	}
 	quSpec := &querySpec{
 		Scols: append(cont.HeadFields, "timestamp", "data"),
@@ -259,10 +283,10 @@ func (cont *Container) Update(tr *Track) *Track {
 	sql := storage.BuildSql(SqlUpdate, quSpec)
 	vals := []any{tr.trackId}
 	for _, k := range cont.HeadFields {
-		vals = append(vals, tr.Head[k])
+		vals = append(vals, tr.head[k])
 	}
-	vals = append(vals, tr.TimeStamp)
-	b, _ := json.Marshal(tr.Data)
+	vals = append(vals, tr.timeStamp)
+	b, _ := json.Marshal(tr.data)
 	vals = append(vals, b)
 	n, _ := cont.Storage.Exec(sql, vals...)
 	if n == 1 {
diff --git a/tests/storage_test.go b/tests/storage_test.go
index 2ce9925..c0352b4 100644
--- a/tests/storage_test.go
+++ b/tests/storage_test.go
@@ -70,16 +70,16 @@ func TrackingTest(t *testing.T, cfg *sql.Cfg, db *sql.Storage) {
 	cont.CreateTable()
 	track := cont.NewTrack(lib.StrSlice{"t01", "john"}, nil)
 	t.AssertEqual(track.TrackId(), lib.Ident(1))
-	t.AssertEqual(track.TimeStamp.Year(), time.Now().Year())
+	t.AssertEqual(track.TimeStamp().Year(), time.Now().Year())
 	tr2 := cont.Get(1)
 	//fmt.Printf("%+v\n", tr2.TimeStamp())
-	t.AssertEqual(tr2.Head["userName"], "john")
+	t.AssertEqual(tr2.Head()["userName"], "john")
 	tr3 := cont.QueryLast("", "john")
-	t.AssertEqual(tr3.Head["taskId"], "t01")
-	tr3.Data = lib.Map{"desc": "go-scopes documentation"}
+	t.AssertEqual(tr3.Head()["taskId"], "t01")
+	tr3.SetData(lib.Map{"desc": "go-scopes documentation"})
 	cont.Update(tr3)
 	tr4 := tracking.Get(db, "rec-1")
-	t.AssertEqual(tr4.Data["desc"], "go-scopes documentation")
+	t.AssertEqual(tr4.Data()["desc"], "go-scopes documentation")
 }
 
 func MessageTest(t *testing.T, cfg *sql.Cfg, db *sql.Storage) {