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&nbsp;&nbsp;&nbsp;&nbsp;<font color="#666666">[INTEGER]</font></td></tr>
                   <tr><td port="b2" align="left">b2&nbsp;&nbsp;&nbsp;&nbsp;<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&nbsp;&nbsp;&nbsp;&nbsp;<font color="#666666">[INTEGER]</font></td></tr>
                 <tr><td port="a2" align="left">a2&nbsp;&nbsp;&nbsp;&nbsp;<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>>];
}
