diff --git a/messages_devtools.go b/messages_devtools.go
index 5a02788..57d55fd 100644
--- a/messages_devtools.go
+++ b/messages_devtools.go
@@ -87,6 +87,14 @@ func init() {
 		"json_editor.valid":  {"Valid JSON", "JSON 有效"},
 		"json_editor.at":     {"Error at line %d, column %d", "错误位于第 %d 行第 %d 列"},
 
+		"schema_tree.label":    {"Schema", "数据库结构"},
+		"schema_tree.empty":    {"No databases", "没有数据库"},
+		"schema_tree.database": {"Database", "数据库"},
+		"schema_tree.table":    {"Table", "表"},
+		"schema_tree.view":     {"View", "视图"},
+		"schema_tree.column":   {"Column", "列"},
+		"schema_tree.index":    {"Index", "索引"},
+
 		"alert_list.empty": {"No alerts", "没有告警"},
 	})
 }
diff --git a/schema_tree.go b/schema_tree.go
new file mode 100644
index 0000000..0c8fed3
--- /dev/null
+++ b/schema_tree.go
@@ -0,0 +1,155 @@
+package mujica
+
+import (
+	"fmt"
+	"log/slog"
+
+	"github.com/egoist/mygo/ui"
+
+	"mujicaui/internal"
+	"mujicaui/theme"
+)
+
+// SchemaKind is what a schema node is. The zero value is SchemaDatabase.
+type SchemaKind int
+
+const (
+	SchemaDatabase SchemaKind = iota
+	SchemaTable
+	SchemaView
+	SchemaColumn
+	SchemaIndex
+)
+
+// SchemaNode is one database object; Detail is a column type or index columns.
+type SchemaNode struct {
+	Name     string
+	Kind     SchemaKind
+	Detail   string
+	Children []SchemaNode
+}
+
+// SchemaTreeState is a SchemaTree's open nodes and choice.
+type SchemaTreeState struct {
+	outline  ui.OutlineState[string]
+	selected int
+	nodes    map[string]*SchemaNode
+	kids     map[string][]string
+	roots    []string
+	src      []SchemaNode
+}
+
+// Selected returns the chosen node's path, as "shop/orders/id", and whether one is chosen.
+func (s *SchemaTreeState) Selected() (string, bool) {
+	if s.selected < 0 || s.selected >= s.outline.Rows() {
+		return "", false
+	}
+	return s.outline.Item(s.selected), true
+}
+
+// SchemaTreeOptions configure a SchemaTree.
+type SchemaTreeOptions struct {
+	// Height of the tree; zero means 360.
+	Height float32
+}
+
+// SchemaTree shows databases, tables, views, columns and indexes as a keyboard tree, virtualized.
+func SchemaTree(c *ui.Context, s *SchemaTreeState, roots []SchemaNode, opts SchemaTreeOptions) ChoiceResult {
+	if s == nil || opts.Height < 0 {
+		panic("mujica: SchemaTree needs a state and Height >= 0")
+	}
+	h := opts.Height
+	if h == 0 {
+		h = 360
+	}
+	schemaIndex(s, roots)
+	k := Tokens(c)
+	d := Density(c)
+	var r ChoiceResult
+	r.Element = codePanel(c).Height(h).Label(msg(c, "schema_tree.label"))
+	r.Element.Children(func() {
+		if len(s.roots) == 0 {
+			codeCaption(c, msg(c, "schema_tree.empty")).Padding(d.Unit() * 4)
+			return
+		}
+		was := s.selected
+		s.outline.List.Selected = &s.selected
+		s.outline.List.Label = func(i int) string { return s.nodes[s.outline.Item(i)].Name }
+		restore := dataSelectTheme(c, 0)
+		e := ui.Outline(c, &s.outline, s.roots, func(p string) []string { return s.kids[p] }, func(p string) {
+			n := s.nodes[p]
+			ui.Row(c).Grow(1).MinWidth(0).MinHeight(d.ControlHeight()-2*d.Unit()).Gap(d.Unit()*2).AlignItems(ui.Center).
+				Label(fmt.Sprintf("%s %s %s", schemaWord(c, n.Kind), n.Name, n.Detail)).Children(func() {
+				sel, _ := s.Selected()
+				codeSelectMark(c, sel == p)
+				letter, col := schemaBadge(k, n.Kind)
+				codeBadge(c, letter, col)
+				ui.Text(c, n.Name).SingleLine().Shrink(0)
+				if n.Detail != "" {
+					codeMono(c, n.Detail).TextColor(k.TextMuted).MinWidth(0)
+				}
+			})
+		}).Grow(1)
+		restore()
+		internal.Ring(e, k.Focus, theme.ControlRadius)
+		r.changed = s.selected != was
+	})
+	if r.changed {
+		p, _ := s.Selected()
+		slog.Debug("mujica: schema_tree select", "path", p)
+	}
+	return r
+}
+
+// schemaIndex maps paths to nodes once per new schema.
+func schemaIndex(s *SchemaTreeState, roots []SchemaNode) {
+	if s.nodes != nil && len(roots) == len(s.src) && (len(roots) == 0 || &roots[0] == &s.src[0]) {
+		return
+	}
+	if s.nodes == nil {
+		s.selected = -1 // nothing chosen at first
+	}
+	s.src, s.nodes, s.kids, s.roots = roots, map[string]*SchemaNode{}, map[string][]string{}, nil
+	var walk func(list []SchemaNode, parent string) []string
+	walk = func(list []SchemaNode, parent string) []string {
+		var paths []string
+		for i := range list {
+			n := &list[i]
+			if n.Name == "" || n.Kind < SchemaDatabase || n.Kind > SchemaIndex {
+				panic(fmt.Sprintf("mujica: SchemaTree node %q needs a Name and a known Kind", n.Name))
+			}
+			p := n.Name
+			if parent != "" {
+				p = parent + "/" + n.Name
+			}
+			if _, dup := s.nodes[p]; dup {
+				panic("mujica: SchemaTree has two nodes at " + p)
+			}
+			s.nodes[p] = n
+			paths = append(paths, p)
+			if len(n.Children) > 0 {
+				s.kids[p] = walk(n.Children, p)
+			}
+		}
+		return paths
+	}
+	s.roots = walk(roots, "")
+}
+
+func schemaBadge(k theme.Tokens, kind SchemaKind) (string, ui.Color) {
+	switch kind {
+	case SchemaDatabase:
+		return "D", k.AccentText
+	case SchemaTable:
+		return "T", k.Info
+	case SchemaView:
+		return "V", k.Success
+	case SchemaIndex:
+		return "I", k.Warning
+	}
+	return "C", k.TextMuted
+}
+
+func schemaWord(c *ui.Context, kind SchemaKind) string {
+	return msg(c, [...]string{"schema_tree.database", "schema_tree.table", "schema_tree.view", "schema_tree.column", "schema_tree.index"}[kind])
+}
diff --git a/schema_tree_test.go b/schema_tree_test.go
new file mode 100644
index 0000000..2a487b1
--- /dev/null
+++ b/schema_tree_test.go
@@ -0,0 +1,90 @@
+package mujica
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/egoist/mygo/ui"
+)
+
+var schemaSample = []SchemaNode{{Name: "court", Kind: SchemaDatabase, Children: []SchemaNode{
+	{Name: "guests", Kind: SchemaTable, Children: []SchemaNode{
+		{Name: "id", Kind: SchemaColumn, Detail: "bigint primary key"},
+		{Name: "name", Kind: SchemaColumn, Detail: "text not null"},
+		{Name: "guests_name_idx", Kind: SchemaIndex, Detail: "(name)"},
+	}},
+	{Name: "seating", Kind: SchemaView},
+}}}
+
+func schemaTester(s *SchemaTreeState, roots []SchemaNode, changes *int) *ui.Tester {
+	return ui.NewTester(func(c *ui.Context) {
+		Use(c, Settings{})
+		if SchemaTree(c, s, roots, SchemaTreeOptions{}).Changed() {
+			*changes++
+		}
+	}, 520, 420)
+}
+
+func TestSchemaTreeKeyboardOpenAndChoose(t *testing.T) {
+	var s SchemaTreeState
+	n := 0
+	tt := schemaTester(&s, schemaSample, &n)
+	if _, ok := s.Selected(); ok || tt.HasText("guests") {
+		t.Fatalf("start: %q", tt.Texts())
+	}
+	tt.Key(0, ui.KeyTab)
+	tt.Key(0, ui.KeyDown) // court
+	tt.Key(0, ui.KeyRight)
+	tt.Key(0, ui.KeyDown) // guests
+	tt.Key(0, ui.KeyRight)
+	for _, s := range []string{"guests", "seating", "bigint primary key", "(name)"} {
+		if !tt.HasText(s) {
+			t.Fatalf("missing %q in %q", s, tt.Texts())
+		}
+	}
+	tt.Key(0, ui.KeyDown)
+	if p, _ := s.Selected(); p != "court/guests/id" || n == 0 {
+		t.Fatalf("selected %q changes %d", p, n)
+	}
+}
+
+func TestSchemaTreeEmptyRulesMany(t *testing.T) {
+	var s SchemaTreeState
+	n := 0
+	tt := schemaTester(&s, nil, &n)
+	if !tt.HasText("No databases") {
+		t.Fatal("empty text")
+	}
+	cols := make([]SchemaNode, 100000)
+	for i := range cols {
+		cols[i] = SchemaNode{Name: fmt.Sprint("c", i), Kind: SchemaColumn}
+	}
+	big := []SchemaNode{{Name: "wide", Kind: SchemaTable, Children: cols}}
+	var bs SchemaTreeState
+	tt = schemaTester(&bs, big, &n)
+	tt.Key(0, ui.KeyTab)
+	tt.Key(0, ui.KeyDown)
+	tt.Key(0, ui.KeyRight)
+	if got := len(tt.Texts()); got > 400 || !tt.HasText("c0") {
+		t.Fatalf("%d texts for 100000 columns", got)
+	}
+	defer func() {
+		if recover() == nil {
+			t.Fatal("duplicate path did not panic")
+		}
+	}()
+	var ds SchemaTreeState
+	schemaTester(&ds, []SchemaNode{{Name: "a"}, {Name: "a"}}, &n)
+}
+
+func TestSchemaTreeSnapshot(t *testing.T) {
+	var s SchemaTreeState
+	snapshotAfter(t, "schema_tree", 500, 300, func(c *ui.Context) {
+		ui.Column(c).Padding(16).Children(func() { SchemaTree(c, &s, schemaSample, SchemaTreeOptions{Height: 260}) })
+	}, func(tt *ui.Tester) {
+		s = SchemaTreeState{}
+		for _, k := range []ui.Key{ui.KeyTab, ui.KeyDown, ui.KeyRight, ui.KeyDown, ui.KeyRight, ui.KeyDown} {
+			tt.Key(0, k)
+		}
+	})
+}
diff --git a/testdata/snapshots/darwin/schema_tree-dark.png b/testdata/snapshots/darwin/schema_tree-dark.png
new file mode 100644
index 0000000..b11c6b2
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diff --git a/testdata/snapshots/darwin/schema_tree-light.png b/testdata/snapshots/darwin/schema_tree-light.png
new file mode 100644
index 0000000..f1e1389
Binary files /dev/null and b/testdata/snapshots/darwin/schema_tree-light.png differ