digraph "label green" {

// Config

graph [rankdir=TB, layout=dot, fontname="Arial"];

node [shape=record, fontsize=14, margin=0.6, fontname="Arial"];

edge [fontsize=10, labelfloat=false, splines=none, fontname="Arial"];

// Tables

subgraph cluster_group_0 {

label="label red";

style = "rounded,filled,setlinewidth(3),bold";

color = "#1F91BE";

fillcolor = "#FFFFFF00"

"b" [shape=none, label=<<table border="0" cellborder="1" cellspacing="0" cellpadding="6">

<tr><td bgcolor="#EFEFEF"><font face="Arial Bold" point-size="18">b</font>&nbsp;&nbsp;&nbsp;&nbsp;<font color="#666666">[]</font></td></tr>

<tr><td port="b" align="left">b <font color="#666666">[INTEGER]</font></td></tr>

<tr><td port="b2" align="left">b2 <font color="#666666">[TEXT]</font></td></tr>

</table>>];

}

"a" [shape=none, label=<<table border="0" cellborder="1" cellspacing="0" cellpadding="6">

<tr><td bgcolor="#EFEFEF"><font face="Arial Bold" point-size="18">a</font>&nbsp;&nbsp;&nbsp;&nbsp;<font color="#666666">[]</font></td></tr>

<tr><td port="a" align="left">a <font color="#666666">[INTEGER]</font></td></tr>

<tr><td port="a2" align="left">a2 <font color="#666666">[TEXT]</font></td></tr>

</table>>];

// Relations

"b":"b" -> "a":"a" [dir=back, arrowtail=crow, taillabel=<<table cellpadding="5" border="0" cellborder="0"><tr><td>FOREIGN KEY (b) REFERENCES a(a)</td></tr></table>>];

}