diff --git a/cmd/doc.go b/cmd/doc.go
index d4273e15a..a2d44cf6a 100644
--- a/cmd/doc.go
+++ b/cmd/doc.go
@@ -23,9 +23,13 @@ package cmd
 import (
 	"fmt"
 	"github.com/k1LoW/tbls/db"
+	"github.com/k1LoW/tbls/output/dot"
 	"github.com/k1LoW/tbls/output/md"
+	"github.com/k1LoW/tbls/schema"
 	"github.com/spf13/cobra"
 	"os"
+	"os/exec"
+	"path/filepath"
 )
 
 // docCmd represents the doc command
@@ -64,13 +68,16 @@ var docCmd = &cobra.Command{
 			}
 		}
 
-		switch outputFormat {
-		case "md":
-			err = md.Output(s, outputPath, force)
-		default:
-			err = fmt.Errorf("Error: %s", "unsupported output format")
+		_, err = exec.Command("which", "dot").Output()
+		if err == nil {
+			err := withDot(s, outputPath)
+			if err != nil {
+				fmt.Println(err)
+			}
 		}
 
+		err = md.Output(s, outputPath, force)
+
 		if err != nil {
 			fmt.Println(err)
 			os.Exit(1)
@@ -78,10 +85,46 @@ var docCmd = &cobra.Command{
 	},
 }
 
+// withDot ...
+func withDot(s *schema.Schema, outputPath string) error {
+	fullPath, err := filepath.Abs(outputPath)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("%s\n", filepath.Join(outputPath, "schema.png"))
+	c := exec.Command("dot", "-Tpng", "-o", filepath.Join(fullPath, "schema.png"))
+	stdin, _ := c.StdinPipe()
+	err = dot.OutputSchema(stdin, s)
+	if err != nil {
+		return err
+	}
+	stdin.Close()
+	err = c.Run()
+	if err != nil {
+		return err
+	}
+	// tables
+	for _, t := range s.Tables {
+		fmt.Printf("%s\n", filepath.Join(outputPath, fmt.Sprintf("%s.png", t.Name)))
+		c := exec.Command("dot", "-Tpng", "-o", filepath.Join(fullPath, fmt.Sprintf("%s.png", t.Name)))
+		stdin, _ := c.StdinPipe()
+		err = dot.OutputSchema(stdin, s)
+		if err != nil {
+			return err
+		}
+		stdin.Close()
+		err = c.Run()
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 func init() {
 	rootCmd.AddCommand(docCmd)
 	docCmd.Flags().BoolVarP(&force, "force", "f", false, "force")
 	docCmd.Flags().BoolVarP(&sort, "sort", "", false, "sort")
 	docCmd.Flags().StringVarP(&additionalDataPath, "add", "a", "", "additional schema data path")
-	docCmd.Flags().StringVarP(&outputFormat, "output", "o", "md", "output format")
 }
diff --git a/cmd/root.go b/cmd/root.go
index 03468beee..e86e26b90 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -36,9 +36,6 @@ var sort bool
 // additionalDataPath is a additional data path
 var additionalDataPath string
 
-// outputFormat is output format
-var outputFormat string
-
 // rootCmd represents the base command when called without any subcommands
 var rootCmd = &cobra.Command{
 	Use:   "tbls",
diff --git a/output/dot/templates.go b/output/dot/templates.go
index 002b105d4..d894c7427 100644
--- a/output/dot/templates.go
+++ b/output/dot/templates.go
@@ -11,19 +11,19 @@ var _Assets5bd148e6149bb9adcdddfcf8cc46d6e3047dbe26 = "digraph {{ .Table.Name }}
 
 // Assets returns go-assets FileSystem
 var Assets = assets.NewFileSystem(map[string][]string{"/": []string{"schema.dot.tmpl", "table.dot.tmpl"}}, map[string]*assets.File{
-	"/": &assets.File{
+	"/table.dot.tmpl": &assets.File{
+		Path:     "/table.dot.tmpl",
+		FileMode: 0x1a4,
+		Mtime:    time.Unix(1527595732, 1527595732000000000),
+		Data:     []byte(_Assets5bd148e6149bb9adcdddfcf8cc46d6e3047dbe26),
+	}, "/": &assets.File{
 		Path:     "/",
 		FileMode: 0x800001ed,
-		Mtime:    time.Unix(1527518947, 1527518947000000000),
+		Mtime:    time.Unix(1527595732, 1527595732000000000),
 		Data:     nil,
 	}, "/schema.dot.tmpl": &assets.File{
 		Path:     "/schema.dot.tmpl",
 		FileMode: 0x1a4,
 		Mtime:    time.Unix(1527512634, 1527512634000000000),
 		Data:     []byte(_Assets21532ae17ad95976ac467eeaeab81f2bb1d537e4),
-	}, "/table.dot.tmpl": &assets.File{
-		Path:     "/table.dot.tmpl",
-		FileMode: 0x1a4,
-		Mtime:    time.Unix(1527518947, 1527518947000000000),
-		Data:     []byte(_Assets5bd148e6149bb9adcdddfcf8cc46d6e3047dbe26),
 	}}, "")
diff --git a/output/md/md.go b/output/md/md.go
index 60d442180..46b167ffb 100644
--- a/output/md/md.go
+++ b/output/md/md.go
@@ -34,8 +34,13 @@ func Output(s *schema.Schema, path string, force bool) error {
 	if err != nil {
 		return err
 	}
+	er := false
+	if _, err := os.Lstat(filepath.Join(fullPath, "schema.png")); err == nil {
+		er = true
+	}
 	err = tmpl.Execute(file, map[string]interface{}{
 		"Schema": s,
+		"er":     er,
 	})
 	if err != nil {
 		return err
@@ -55,8 +60,13 @@ func Output(s *schema.Schema, path string, force bool) error {
 		if err != nil {
 			return err
 		}
+		er := false
+		if _, err := os.Lstat(filepath.Join(fullPath, fmt.Sprintf("%s.png", t.Name))); err == nil {
+			er = true
+		}
 		err = tmpl.Execute(file, map[string]interface{}{
 			"Table": t,
+			"er":    er,
 		})
 		if err != nil {
 			return err
@@ -84,8 +94,16 @@ func Diff(s *schema.Schema, path string) error {
 	f, _ := Assets.Open(filepath.Join("/", "index.md.tmpl"))
 	bs, _ := ioutil.ReadAll(f)
 	tmpl, err := template.New("index").Parse(string(bs))
+	if err != nil {
+		return err
+	}
+	er := false
+	if _, err := os.Lstat(filepath.Join(fullPath, "schema.png")); err == nil {
+		er = true
+	}
 	err = tmpl.Execute(a, map[string]interface{}{
 		"Schema": s,
+		"er":     er,
 	})
 	if err != nil {
 		return err
@@ -111,8 +129,16 @@ func Diff(s *schema.Schema, path string) error {
 		f, _ := Assets.Open(filepath.Join("/", "table.md.tmpl"))
 		bs, _ := ioutil.ReadAll(f)
 		tmpl, err := template.New(t.Name).Parse(string(bs))
+		if err != nil {
+			return err
+		}
+		er := false
+		if _, err := os.Lstat(filepath.Join(fullPath, fmt.Sprintf("%s.png", t.Name))); err == nil {
+			er = true
+		}
 		err = tmpl.Execute(a, map[string]interface{}{
 			"Table": t,
+			"er":    er,
 		})
 		if err != nil {
 			return err
diff --git a/output/md/templates.go b/output/md/templates.go
index 98142a51f..36d59bf10 100644
--- a/output/md/templates.go
+++ b/output/md/templates.go
@@ -6,24 +6,24 @@ import (
 	"github.com/jessevdk/go-assets"
 )
 
-var _Assetsac44302fb6150a621aa9d04a0350aac972bf7e18 = "# {{ .Table.Name }}\n\n## Description\n\n{{ .Table.Comment }}\n\n## Columns\n\n| Name | Type | Default | Nullable | Children | Parents | Comment |\n| ---- | ---- | ------- | -------- | -------- | ------- | ------- |\n{{- range $i, $c := .Table.Columns }}\n| {{ $c.Name }} | {{ $c.Type }} | {{ $c.Default.String }} | {{ $c.Nullable }} | {{ range $ii, $r := $c.ChildRelations -}}[{{ $r.Table.Name }}]({{ $r.Table.Name }}.md) {{ end }} | {{ range $ii, $r := $c.ParentRelations -}}[{{ $r.ParentTable.Name }}]({{ $r.ParentTable.Name }}.md) {{ end }} | {{ $c.Comment }} |\n{{- end }}\n\n## Constraints\n\n| Name | Type | Def |\n| ---- | ---- | --- |\n{{- range $i, $c := .Table.Constraints }}\n| {{ $c.Name }} | {{ $c.Type }} | {{ $c.Def }} |\n{{- end }}\n\n## Indexes\n\n| Name | Def |\n| ---- | --- |\n{{- range $i, $idx := .Table.Indexes }}\n| {{ $idx.Name }} | {{ $idx.Def }} |\n{{- end }}\n\n---\n\n> Generated by [tbls](https://github.com/k1LoW/tbls)"
-var _Assets43889384df1c6f74d764c29d91b9d5637eb46061 = "# {{ .Schema.Name }}\n\n## Tables\n\n| Name | Columns | Comment | Type |\n| ---- | ------- | ------- | ---- |\n{{- range $i, $t := .Schema.Tables }}\n| [{{ $t.Name }}]({{ $t.Name }}.md) | {{ len $t.Columns }} | {{ $t.Comment }} | {{ $t.Type }} |\n{{- end }}\n\n---\n\n> Generated by [tbls](https://github.com/k1LoW/tbls)"
+var _Assets43889384df1c6f74d764c29d91b9d5637eb46061 = "# {{ .Schema.Name }}\n\n## Tables\n\n| Name | Columns | Comment | Type |\n| ---- | ------- | ------- | ---- |\n{{- range $i, $t := .Schema.Tables }}\n| [{{ $t.Name }}]({{ $t.Name }}.md) | {{ len $t.Columns }} | {{ $t.Comment }} | {{ $t.Type }} |\n{{- end }}\n\n{{ if .er -}}\n## Relations\n\n![er](schema.png)\n{{- end }}\n\n---\n\n> Generated by [tbls](https://github.com/k1LoW/tbls)"
+var _Assetsac44302fb6150a621aa9d04a0350aac972bf7e18 = "# {{ .Table.Name }}\n\n## Description\n\n{{ .Table.Comment }}\n\n## Columns\n\n| Name | Type | Default | Nullable | Children | Parents | Comment |\n| ---- | ---- | ------- | -------- | -------- | ------- | ------- |\n{{- range $i, $c := .Table.Columns }}\n| {{ $c.Name }} | {{ $c.Type }} | {{ $c.Default.String }} | {{ $c.Nullable }} | {{ range $ii, $r := $c.ChildRelations -}}[{{ $r.Table.Name }}]({{ $r.Table.Name }}.md) {{ end }} | {{ range $ii, $r := $c.ParentRelations -}}[{{ $r.ParentTable.Name }}]({{ $r.ParentTable.Name }}.md) {{ end }} | {{ $c.Comment }} |\n{{- end }}\n\n## Constraints\n\n| Name | Type | Def |\n| ---- | ---- | --- |\n{{- range $i, $c := .Table.Constraints }}\n| {{ $c.Name }} | {{ $c.Type }} | {{ $c.Def }} |\n{{- end }}\n\n## Indexes\n\n| Name | Def |\n| ---- | --- |\n{{- range $i, $idx := .Table.Indexes }}\n| {{ $idx.Name }} | {{ $idx.Def }} |\n{{- end }}\n\n{{ if .er -}}\n## Relations\n\n![er]({{ .Table.Name }}.png)\n{{- end }}\n\n---\n\n> Generated by [tbls](https://github.com/k1LoW/tbls)"
 
 // Assets returns go-assets FileSystem
 var Assets = assets.NewFileSystem(map[string][]string{"/": []string{"index.md.tmpl", "table.md.tmpl"}}, map[string]*assets.File{
 	"/": &assets.File{
 		Path:     "/",
 		FileMode: 0x800001ed,
-		Mtime:    time.Unix(1527296235, 1527296235000000000),
+		Mtime:    time.Unix(1527597737, 1527597737000000000),
 		Data:     nil,
 	}, "/index.md.tmpl": &assets.File{
 		Path:     "/index.md.tmpl",
 		FileMode: 0x1a4,
-		Mtime:    time.Unix(1526904993, 1526904993000000000),
+		Mtime:    time.Unix(1527597737, 1527597737000000000),
 		Data:     []byte(_Assets43889384df1c6f74d764c29d91b9d5637eb46061),
 	}, "/table.md.tmpl": &assets.File{
 		Path:     "/table.md.tmpl",
 		FileMode: 0x1a4,
-		Mtime:    time.Unix(1527296235, 1527296235000000000),
+		Mtime:    time.Unix(1527597735, 1527597735000000000),
 		Data:     []byte(_Assetsac44302fb6150a621aa9d04a0350aac972bf7e18),
 	}}, "")
diff --git a/output/md/templates/index.md.tmpl b/output/md/templates/index.md.tmpl
index 4b5caa024..b20c9cf74 100644
--- a/output/md/templates/index.md.tmpl
+++ b/output/md/templates/index.md.tmpl
@@ -8,6 +8,12 @@
 | [{{ $t.Name }}]({{ $t.Name }}.md) | {{ len $t.Columns }} | {{ $t.Comment }} | {{ $t.Type }} |
 {{- end }}
 
+{{ if .er -}}
+## Relations
+
+![er](schema.png)
+{{- end }}
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/output/md/templates/table.md.tmpl b/output/md/templates/table.md.tmpl
index 12272199c..5235002de 100644
--- a/output/md/templates/table.md.tmpl
+++ b/output/md/templates/table.md.tmpl
@@ -28,6 +28,12 @@
 | {{ $idx.Name }} | {{ $idx.Def }} |
 {{- end }}
 
+{{ if .er -}}
+## Relations
+
+![er]({{ .Table.Name }}.png)
+{{- end }}
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql/CamelizeTable.md b/sample/mysql/CamelizeTable.md
index f396fe509..f59b41a33 100644
--- a/sample/mysql/CamelizeTable.md
+++ b/sample/mysql/CamelizeTable.md
@@ -23,6 +23,10 @@
 | ---- | --- |
 | PRIMARY | PRIMARY KEY (id) USING BTREE |
 
+## Relations
+
+![er](CamelizeTable.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql/CamelizeTable.png b/sample/mysql/CamelizeTable.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql/CamelizeTable.png differ
diff --git a/sample/mysql/README.md b/sample/mysql/README.md
index 4d3ff1dff..51a2ff1f3 100644
--- a/sample/mysql/README.md
+++ b/sample/mysql/README.md
@@ -12,6 +12,10 @@
 | [posts](posts.md) | 7 | Posts table | BASE TABLE |
 | [users](users.md) | 6 | Users table | BASE TABLE |
 
+## Relations
+
+![er](schema.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql/comment_stars.md b/sample/mysql/comment_stars.md
index f7cfc6248..eda5010e4 100644
--- a/sample/mysql/comment_stars.md
+++ b/sample/mysql/comment_stars.md
@@ -33,6 +33,10 @@
 | PRIMARY | PRIMARY KEY (id) USING BTREE |
 | user_id | UNIQUE KEY user_id (user_id, comment_post_id, comment_user_id) USING BTREE |
 
+## Relations
+
+![er](comment_stars.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql/comment_stars.png b/sample/mysql/comment_stars.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql/comment_stars.png differ
diff --git a/sample/mysql/comments.md b/sample/mysql/comments.md
index b6d58c6cb..32195abac 100644
--- a/sample/mysql/comments.md
+++ b/sample/mysql/comments.md
@@ -33,6 +33,10 @@
 | PRIMARY | PRIMARY KEY (id) USING BTREE |
 | post_id | UNIQUE KEY post_id (post_id, user_id) USING BTREE |
 
+## Relations
+
+![er](comments.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql/comments.png b/sample/mysql/comments.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql/comments.png differ
diff --git a/sample/mysql/logs.md b/sample/mysql/logs.md
index 46ddf3d24..8d6412960 100644
--- a/sample/mysql/logs.md
+++ b/sample/mysql/logs.md
@@ -28,6 +28,10 @@
 | ---- | --- |
 | PRIMARY | PRIMARY KEY (id) USING BTREE |
 
+## Relations
+
+![er](logs.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql/logs.png b/sample/mysql/logs.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql/logs.png differ
diff --git a/sample/mysql/post_comments.md b/sample/mysql/post_comments.md
index 14665fe0c..022c0f075 100644
--- a/sample/mysql/post_comments.md
+++ b/sample/mysql/post_comments.md
@@ -26,6 +26,10 @@ VIEW
 | Name | Def |
 | ---- | --- |
 
+## Relations
+
+![er](post_comments.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql/post_comments.png b/sample/mysql/post_comments.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql/post_comments.png differ
diff --git a/sample/mysql/posts.md b/sample/mysql/posts.md
index d2b8827d4..337619c87 100644
--- a/sample/mysql/posts.md
+++ b/sample/mysql/posts.md
@@ -32,6 +32,10 @@ Posts table
 | PRIMARY | PRIMARY KEY (id) USING BTREE |
 | user_id | UNIQUE KEY user_id (user_id, title) USING BTREE |
 
+## Relations
+
+![er](posts.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql/posts.png b/sample/mysql/posts.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql/posts.png differ
diff --git a/sample/mysql/schema.png b/sample/mysql/schema.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql/schema.png differ
diff --git a/sample/mysql/users.md b/sample/mysql/users.md
index a39331647..b5c8a6f83 100644
--- a/sample/mysql/users.md
+++ b/sample/mysql/users.md
@@ -31,6 +31,10 @@ Users table
 | email | UNIQUE KEY email (email) USING BTREE |
 | username | UNIQUE KEY username (username) USING BTREE |
 
+## Relations
+
+![er](users.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql/users.png b/sample/mysql/users.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql/users.png differ
diff --git a/sample/mysql8/CamelizeTable.md b/sample/mysql8/CamelizeTable.md
index f396fe509..f59b41a33 100644
--- a/sample/mysql8/CamelizeTable.md
+++ b/sample/mysql8/CamelizeTable.md
@@ -23,6 +23,10 @@
 | ---- | --- |
 | PRIMARY | PRIMARY KEY (id) USING BTREE |
 
+## Relations
+
+![er](CamelizeTable.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql8/CamelizeTable.png b/sample/mysql8/CamelizeTable.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql8/CamelizeTable.png differ
diff --git a/sample/mysql8/README.md b/sample/mysql8/README.md
index 4d3ff1dff..51a2ff1f3 100644
--- a/sample/mysql8/README.md
+++ b/sample/mysql8/README.md
@@ -12,6 +12,10 @@
 | [posts](posts.md) | 7 | Posts table | BASE TABLE |
 | [users](users.md) | 6 | Users table | BASE TABLE |
 
+## Relations
+
+![er](schema.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql8/comment_stars.md b/sample/mysql8/comment_stars.md
index 25fa684b2..7b329795a 100644
--- a/sample/mysql8/comment_stars.md
+++ b/sample/mysql8/comment_stars.md
@@ -33,6 +33,10 @@
 | PRIMARY | PRIMARY KEY (id) USING BTREE |
 | user_id | UNIQUE KEY user_id (user_id, comment_post_id, comment_user_id) USING BTREE |
 
+## Relations
+
+![er](comment_stars.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql8/comment_stars.png b/sample/mysql8/comment_stars.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql8/comment_stars.png differ
diff --git a/sample/mysql8/comments.md b/sample/mysql8/comments.md
index b6d58c6cb..32195abac 100644
--- a/sample/mysql8/comments.md
+++ b/sample/mysql8/comments.md
@@ -33,6 +33,10 @@
 | PRIMARY | PRIMARY KEY (id) USING BTREE |
 | post_id | UNIQUE KEY post_id (post_id, user_id) USING BTREE |
 
+## Relations
+
+![er](comments.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql8/comments.png b/sample/mysql8/comments.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql8/comments.png differ
diff --git a/sample/mysql8/logs.md b/sample/mysql8/logs.md
index 46ddf3d24..8d6412960 100644
--- a/sample/mysql8/logs.md
+++ b/sample/mysql8/logs.md
@@ -28,6 +28,10 @@
 | ---- | --- |
 | PRIMARY | PRIMARY KEY (id) USING BTREE |
 
+## Relations
+
+![er](logs.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql8/logs.png b/sample/mysql8/logs.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql8/logs.png differ
diff --git a/sample/mysql8/post_comments.md b/sample/mysql8/post_comments.md
index 14665fe0c..022c0f075 100644
--- a/sample/mysql8/post_comments.md
+++ b/sample/mysql8/post_comments.md
@@ -26,6 +26,10 @@ VIEW
 | Name | Def |
 | ---- | --- |
 
+## Relations
+
+![er](post_comments.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql8/post_comments.png b/sample/mysql8/post_comments.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql8/post_comments.png differ
diff --git a/sample/mysql8/posts.md b/sample/mysql8/posts.md
index d2b8827d4..337619c87 100644
--- a/sample/mysql8/posts.md
+++ b/sample/mysql8/posts.md
@@ -32,6 +32,10 @@ Posts table
 | PRIMARY | PRIMARY KEY (id) USING BTREE |
 | user_id | UNIQUE KEY user_id (user_id, title) USING BTREE |
 
+## Relations
+
+![er](posts.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql8/posts.png b/sample/mysql8/posts.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql8/posts.png differ
diff --git a/sample/mysql8/schema.png b/sample/mysql8/schema.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql8/schema.png differ
diff --git a/sample/mysql8/users.md b/sample/mysql8/users.md
index 5326038a3..e68358aee 100644
--- a/sample/mysql8/users.md
+++ b/sample/mysql8/users.md
@@ -31,6 +31,10 @@ Users table
 | email | UNIQUE KEY email (email) USING BTREE |
 | username | UNIQUE KEY username (username) USING BTREE |
 
+## Relations
+
+![er](users.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/mysql8/users.png b/sample/mysql8/users.png
new file mode 100644
index 000000000..157bdc612
Binary files /dev/null and b/sample/mysql8/users.png differ
diff --git a/sample/postgres/CamelizeTable.md b/sample/postgres/CamelizeTable.md
index bade2a7d9..5bc5b0d8c 100644
--- a/sample/postgres/CamelizeTable.md
+++ b/sample/postgres/CamelizeTable.md
@@ -21,6 +21,10 @@
 | Name | Def |
 | ---- | --- |
 
+## Relations
+
+![er](CamelizeTable.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/postgres/CamelizeTable.png b/sample/postgres/CamelizeTable.png
new file mode 100644
index 000000000..1424faab9
Binary files /dev/null and b/sample/postgres/CamelizeTable.png differ
diff --git a/sample/postgres/README.md b/sample/postgres/README.md
index 188b32b1c..eabc2155e 100644
--- a/sample/postgres/README.md
+++ b/sample/postgres/README.md
@@ -12,6 +12,10 @@
 | [post_comments](post_comments.md) | 7 |  | VIEW |
 | [CamelizeTable](CamelizeTable.md) | 2 |  | BASE TABLE |
 
+## Relations
+
+![er](schema.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/postgres/comment_stars.md b/sample/postgres/comment_stars.md
index 89c3e84a8..3e69aa25f 100644
--- a/sample/postgres/comment_stars.md
+++ b/sample/postgres/comment_stars.md
@@ -29,6 +29,10 @@
 | ---- | --- |
 | comment_stars_user_id_comment_post_id_comment_user_id_key | CREATE UNIQUE INDEX comment_stars_user_id_comment_post_id_comment_user_id_key ON public.comment_stars USING btree (user_id, comment_post_id, comment_user_id) |
 
+## Relations
+
+![er](comment_stars.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/postgres/comment_stars.png b/sample/postgres/comment_stars.png
new file mode 100644
index 000000000..1424faab9
Binary files /dev/null and b/sample/postgres/comment_stars.png differ
diff --git a/sample/postgres/comments.md b/sample/postgres/comments.md
index 6a063ee34..2838a5204 100755
--- a/sample/postgres/comments.md
+++ b/sample/postgres/comments.md
@@ -32,6 +32,10 @@
 | comments_post_id_user_id_key | CREATE UNIQUE INDEX comments_post_id_user_id_key ON public.comments USING btree (post_id, user_id) |
 | comments_post_id_user_id_idx | CREATE INDEX comments_post_id_user_id_idx ON public.comments USING btree (post_id, user_id) |
 
+## Relations
+
+![er](comments.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/postgres/comments.png b/sample/postgres/comments.png
new file mode 100644
index 000000000..1424faab9
Binary files /dev/null and b/sample/postgres/comments.png differ
diff --git a/sample/postgres/logs.md b/sample/postgres/logs.md
index a18ed0e42..282817221 100644
--- a/sample/postgres/logs.md
+++ b/sample/postgres/logs.md
@@ -26,6 +26,10 @@
 | Name | Def |
 | ---- | --- |
 
+## Relations
+
+![er](logs.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/postgres/logs.png b/sample/postgres/logs.png
new file mode 100644
index 000000000..1424faab9
Binary files /dev/null and b/sample/postgres/logs.png differ
diff --git a/sample/postgres/post_comments.md b/sample/postgres/post_comments.md
index e19e7acae..851f109fa 100644
--- a/sample/postgres/post_comments.md
+++ b/sample/postgres/post_comments.md
@@ -26,6 +26,10 @@
 | Name | Def |
 | ---- | --- |
 
+## Relations
+
+![er](post_comments.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/postgres/post_comments.png b/sample/postgres/post_comments.png
new file mode 100644
index 000000000..1424faab9
Binary files /dev/null and b/sample/postgres/post_comments.png differ
diff --git a/sample/postgres/posts.md b/sample/postgres/posts.md
index 77230d7a6..8b776fcc6 100755
--- a/sample/postgres/posts.md
+++ b/sample/postgres/posts.md
@@ -33,6 +33,10 @@ Posts table
 | posts_user_id_title_key | CREATE UNIQUE INDEX posts_user_id_title_key ON public.posts USING btree (user_id, title) |
 | posts_user_id_idx | CREATE INDEX posts_user_id_idx ON public.posts USING btree (user_id) |
 
+## Relations
+
+![er](posts.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/postgres/posts.png b/sample/postgres/posts.png
new file mode 100644
index 000000000..1424faab9
Binary files /dev/null and b/sample/postgres/posts.png differ
diff --git a/sample/postgres/schema.png b/sample/postgres/schema.png
new file mode 100644
index 000000000..1424faab9
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diff --git a/sample/postgres/users.md b/sample/postgres/users.md
index f12116738..63670ab3e 100755
--- a/sample/postgres/users.md
+++ b/sample/postgres/users.md
@@ -32,6 +32,10 @@ Users table
 | users_username_key | CREATE UNIQUE INDEX users_username_key ON public.users USING btree (username) |
 | users_email_key | CREATE UNIQUE INDEX users_email_key ON public.users USING btree (email) |
 
+## Relations
+
+![er](users.png)
+
 ---
 
 > Generated by [tbls](https://github.com/k1LoW/tbls)
\ No newline at end of file
diff --git a/sample/postgres/users.png b/sample/postgres/users.png
new file mode 100644
index 000000000..1424faab9
Binary files /dev/null and b/sample/postgres/users.png differ