Take the 2-minute tour ×
TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. It's 100% free, no registration required.

I am looking into a feasible way of drawing relationships between Elements from a database. An example: Element x is related to Element Y via the Role "sister".

Relationships exist in the form 1:1, 1:n or m:n, so one element may link to >1 other elements, there are also >1 element types and >1 role types.

Right now it is done manually in Powerpoint, which is really prone to errors. Is there a suitable way to draw these diagrams via TikZ/PGF or any other software? I'd love to write some SQL script to get me the list of elements with their relationship and have e.g. Python prepare the TeX Code. The major challenge is for me, that I have no clue how many elements come from the database and I would like to have LaTeX do the positioning.

enter image description here

share|improve this question
3  
I think GraphViz can help. :) And we can also use the dot2texi package to embed graphs written in .dot in our .tex documents. :) –  Paulo Cereda Oct 20 '12 at 0:28
2  
Another possibility is tikz-er2. You find also an example here. –  Claudio Fiandrino Oct 20 '12 at 9:56
    
Would either of you post GraphiViz or tikz-er2 as answer, then i'll accept. Both are quite good and will help me a lot. –  Uwe Ziegenhagen Oct 21 '12 at 15:07
    
Look at tex.stackexchange.com/questions/58389/…. Is it what you searh to ? –  madit Oct 24 '12 at 14:09
add comment

1 Answer

up vote 14 down vote accepted

As said in the comments, two approaches could be used. I first introduce them and later on I'll try to explain a bit which are the pros and cons of both.

I start with the tikz-er2 package: it's not available on CTAN, thus one should install it by hand.

The code:

\documentclass[a4paper,11pt,x11names]{article}

\usepackage{tikz-er2}
\tikzset{every entity/.style={draw=orange, fill=orange!20}}
\tikzset{every attribute/.style={draw=MediumPurple1, fill=MediumPurple1!20}}
\tikzset{every relationship/.style={draw=Chartreuse2, fill=Chartreuse2!20}}

\begin{document}
\begin{tikzpicture}[node distance=7em]
\node[entity] (person) {Person};
\node[attribute] (pid) [left of=person] {\key{ID}} edge (person);
\node[attribute] (name) [above left of=person] {Name} edge (person);
\node[multi attribute] (phone) [above of=person] {Phone} edge (person);
\node[attribute] (address) [above right of=person] {Address} edge (person);
\node[attribute] (street) [above right of=address] {Street} edge (address);
\node[attribute] (city) [right of=address] {City} edge (address);
\node[derived attribute] (age) [right of=person] {Age} edge (person);

\node[relationship] (uses) [below of=person] {Uses} edge (person);
\node[entity] (tool) [below of=uses] {Tool} edge[total] (uses);
\node[attribute] (tid) [left of=tool] {\key{ID}} edge (tool);
\node[attribute] (tname) [right of =tool] {Name} edge (tool);
\end{tikzpicture}

\end{document}

The result:

enter image description here

Here is the GraphViz method. The .dot language could be used in LaTeX documents inside the environment dot2tex, but this requires the dot2texi package and the document should be compiled with -shell-escape.

Consider the following example:

\documentclass[a4paper,11pt,x11names]{article}
\usepackage{tikz}
\usetikzlibrary{automata,shapes}

\usepackage{dot2texi}
\tikzset{entity/.style={draw=orange, fill=orange!20}}
\tikzset{attribute/.style={ellipse,draw=MediumPurple1, fill=MediumPurple1!20}}
\tikzset{multi attribute/.style={ellipse,draw=MediumPurple1, fill=MediumPurple1!20,double}}
\tikzset{derived attribute/.style={ellipse,draw=MediumPurple1, fill=MediumPurple1!20,dashed}}
\tikzset{relationship/.style={diamond,draw=Chartreuse2, fill=Chartreuse2!20}}
\tikzset{simple relation/.style={-}}
\tikzset{total relation/.style={-,double}}

\begin{document}
\begin{tikzpicture}[
every state/.style={draw=blue!50,very thick,fill=blue!20},]
\begin{dot2tex}[styleonly,codeonly,neato,options=-s -tmath]
digraph G {
d2ttikzedgelabels = true;
edge [lblstyle="auto",topath="-",style="simple relation"];
// nodes
Person [style="entity"];
pid [style="attribute",label="\underline{ID}"];
Attribute [style="attribute"];
Name [style="attribute"];
Phone [style="multi attribute"];
Address [style="attribute"];
Street [style="attribute"];
City [style="attribute"];
Age [style="derived attribute"];
Uses [style="relationship"];
Tool [style="entity"];
tid [style="attribute",label="\underline{ID}"];
tname [style="attribute",label="Name"];
// edges
Person -> pid;
Person -> Attribute;
Person -> Name;
Person -> Phone;
Person -> Address -> Street;
Person -> City;
Person -> Age;
Person -> Uses;
Tool -> tid;
Tool -> tname;
Tool -> Uses[style="total relation"];
}
\end{dot2tex}
\end{tikzpicture}    

\end{document}

as test_dot.tex. Now, compiling it with pdflatex -shell-escape test_dot.tex, you will end up with:

enter image description here

Notice, besised reading the dot2texi documentation, you will find also further details on http://www.fauskes.net/code/dot2tex/documentation/.

Now, which are the pros/cons of these approaches?

In general GraphViz is used for large graphs because it's more suitable since you don't have to specify in which positions each node should be placed. With tikz-er2, instead, you should. Ultimately, this is a first parameter to decide which one use: look at the database dimensions. Notice that GraphViz place with its own algorithms the nodes, so if you really want to deploy something in a particular manner, perhaps you should come back.

With GraphViz, as it is possible to see, one should declare the styles in which all elements are drawn, even the base ones. With tikz-er2 you just have to customize a bit the aspect, but IMHO this is a minor point.


Addition 17/01/2013

Almost by chance I discovered recently that TikZ has its own er library: refer to section 31 Entity-Relationship Diagram Drawing Library of the pgfmanual version October 25, 2010. The usage is almost identical to the example provided with tikz-er2.

Another approach, instead, could be object-oriented. Here is a possible start although a more complete and powerful version of the library is under development (repository: https://github.com/cfiandra/er-oo).

I defined a simple library er-oo as:

\usepgfmodule{oo}
\usetikzlibrary{automata,shapes}

\definecolor{er-purple}{rgb}{.67,.51,1}
\definecolor{er-green}{rgb}{.464,.932,0}

% Entity Class
\pgfooclass{entity}{

 \attribute text;
 \attribute border color=orange;
 \attribute fill color=orange!20;
 \attribute text color=black;
 \attribute label;
 \attribute width=1.75cm;
 \attribute height=1cm;

 \method entity() {
 }

 \method text(#1) {
  \pgfooset{text}{#1}
  }

 \method set border color(#1) {
  \pgfooset{border color}{#1}
 }

 \method set fill color(#1) {
  \pgfooset{fill color}{#1}
 }

 \method set text color(#1) {
  \pgfooset{text color}{#1}
 }

 \method set label(#1) {
  \pgfooset{label}{#1}
 }

 \method set width(#1) {
  \pgfooset{width}{#1}
 }

 \method set height(#1) {
  \pgfooset{height}{#1}
 }

 \method draw(#1,#2) {
  \node [rectangle,
    draw=\pgfoovalueof{border color},
    fill=\pgfoovalueof{fill color},
    text=\pgfoovalueof{text color},
    minimum width=\pgfoovalueof{width},
    minimum height=\pgfoovalueof{height},
    ] (\pgfoovalueof{label}) at (#1,#2) {\pgfoovalueof{text}};
 }

 \method place(#1) {
  \node [rectangle,
    draw=\pgfoovalueof{border color},
    fill=\pgfoovalueof{fill color},
    text=\pgfoovalueof{text color},
    minimum width=\pgfoovalueof{width},
    minimum height=\pgfoovalueof{height},
    #1
    ] (\pgfoovalueof{label}) {\pgfoovalueof{text}};
 }

 \method connect(#1) {
  \draw[-] (\pgfoovalueof{label})--(#1);
 }

 \method multi connect(#1) {
  \foreach \i in {#1}{
    \draw[-] (\pgfoovalueof{label})--(\i);
  }  
 }

 \method total relation(#1) {
  \draw[-,double] (\pgfoovalueof{label})--(#1);
 }

}

% Relationship Class
\pgfooclass{relationship}{

 \attribute text;
 \attribute border color=er-green;
 \attribute fill color=er-green!20;
 \attribute text color=black;
 \attribute label;
 \attribute width=1.5cm;
 \attribute height=0.75cm;

 \method relationship() {
 }

 \method text(#1) {
  \pgfooset{text}{#1}
  }

 \method set border color(#1) {
  \pgfooset{border color}{#1}
 }

 \method set fill color(#1) {
  \pgfooset{fill color}{#1}
 }

 \method set text color(#1) {
  \pgfooset{text color}{#1}
 }

 \method set label(#1) {
  \pgfooset{label}{#1}
 }

 \method set width(#1) {
  \pgfooset{width}{#1}
 }

 \method set height(#1) {
  \pgfooset{height}{#1}
 }

 \method draw(#1,#2) {
  \node [diamond,
    draw=\pgfoovalueof{border color},
    fill=\pgfoovalueof{fill color},
    text=\pgfoovalueof{text color},
    minimum width=\pgfoovalueof{width},
    minimum height=\pgfoovalueof{height},
    ] (\pgfoovalueof{label}) at (#1,#2) {\pgfoovalueof{text}};
 }

 \method place(#1) {
  \node [diamond,
    draw=\pgfoovalueof{border color},
    fill=\pgfoovalueof{fill color},
    text=\pgfoovalueof{text color},
    minimum width=\pgfoovalueof{width},
    minimum height=\pgfoovalueof{height},
    #1
    ] (\pgfoovalueof{label}) {\pgfoovalueof{text}};
 }

 \method connect(#1) {
  \draw[-] (\pgfoovalueof{label})--(#1);
 }

 \method double connect(#1) {
  \draw[-,double,double distance=1.5pt] (\pgfoovalueof{label})--(#1);
 }

 \method multi connect(#1) {
  \foreach \i in {#1}{
    \draw[-] (\pgfoovalueof{label})--(\i);
  }  
 }

 \method total relation(#1) {
  \draw[-,double] (\pgfoovalueof{label})--(#1);
 }

}

% Attribute Class
\tikzset{multi attribute/.style={double,double distance=1.5pt}}
\tikzset{derived attribute/.style={dashed}}
\tikzset{attribute type/.style={thick,#1}}

\pgfooclass{attribute}{

 \attribute text;
 \attribute border color=er-purple;
 \attribute fill color=er-purple!20;
 \attribute text color=black;
 \attribute label;
 \attribute type;
 \attribute width=1.5cm;
 \attribute height=0.35cm;

 \method attribute() {
 }

 \method text(#1) {
  \pgfooset{text}{#1}
  }

 \method set border color(#1) {
  \pgfooset{border color}{#1}
 }

 \method set fill color(#1) {
  \pgfooset{fill color}{#1}
 }

 \method set text color(#1) {
  \pgfooset{text color}{#1}
 }

 \method set label(#1) {
  \pgfooset{label}{#1}
 }

 \method set type(#1) {
  \pgfooset{type}{#1}
 }

 \method set width(#1) {
  \pgfooset{width}{#1}
 }

 \method set height(#1) {
  \pgfooset{height}{#1}
 }

 \method draw(#1,#2) {
  \node [ellipse,
    attribute type={\pgfoovalueof{type}},
    draw=\pgfoovalueof{border color},
    fill=\pgfoovalueof{fill color},
    text=\pgfoovalueof{text color},
    minimum width=\pgfoovalueof{width},
    minimum height=\pgfoovalueof{height},
    ] (\pgfoovalueof{label}) at (#1,#2) {\pgfoovalueof{text}};
 }

 \method place(#1) {
  \node [ellipse,
    attribute type={\pgfoovalueof{type}},
    draw=\pgfoovalueof{border color},
    fill=\pgfoovalueof{fill color},
    text=\pgfoovalueof{text color},
    minimum width=\pgfoovalueof{width},
    minimum height=\pgfoovalueof{height},
    #1
    ] (\pgfoovalueof{label}) {\pgfoovalueof{text}};
 }

 \method connect(#1) {
  \draw[-] (\pgfoovalueof{label})--(#1);
 }

 \method multi connect(#1) {
  \foreach \i in {#1}{
    \draw[-] (\pgfoovalueof{label})--(\i);
  }  
 }

 \method total relation(#1) {
  \draw[-,double] (\pgfoovalueof{label})--(#1);
 }

}

thus this file should be named tikzlibraryer-oo.code.tex in order to be used in the document as:

\usetikzlibrary{er-oo}

Now, being sure that tikzlibraryer-oo.code.tex is in the same directory of the main file, in the document one could proceed as follows:

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{er-oo}

\begin{document}

\begin{tikzpicture}[node distance=2.75cm]
% new objects
\pgfoonew \myentity=new entity()
\pgfoonew \myrel=new relationship()
\pgfoonew \myattr=new attribute()

% entity tool
\myentity.set label(tool)
\myentity.text(Tool)
\myentity.draw(1,0)

\myattr.set label(tool-id)
\myattr.text(\underline{ID})
\myattr.place(left of=tool)

\myattr.set label(tool-name)
\myattr.text(Name)
\myattr.place(right of=tool)

\myentity.multi connect(tool-id,tool-name)

% relation
\myrel.set label(rel)
\myrel.text(Uses)
\myrel.place(above of=tool)
\myrel.double connect(tool)

% entity person
\myentity.set text color(blue) % just to change something with the proper method
\myentity.set label(per)
\myentity.text(Person)
\myentity.place(above of=rel)

\myattr.set label(per-id)
\myattr.text(\underline{ID})
\myattr.place(left of=per)

\myattr.set type(derived attribute)
\myattr.set label(per-age)
\myattr.text(Age)
\myattr.place(right of=per)

\myattr.set type() % to reset the derived attribute style
\myattr.set label(per-name)
\myattr.text(Name)
\myattr.place(above left of=per)

\myattr.set type(multi attribute)
\myattr.set label(per-phone)
\myattr.text(Phone)
\myattr.place(above of=per)

\myattr.set type() % to reset the multi attribute style
\myattr.set label(per-addr)
\myattr.text(Address)
\myattr.place(above right of=per)

\myattr.set label(street)
\myattr.text(Street)
\myattr.place(above right of=per-addr)
\myattr.connect(per-addr)

\myattr.set label(city)
\myattr.text(City)
\myattr.place(right of=per-addr)
\myattr.connect(per-addr)

\myentity.multi connect(per-id,per-age,per-name,per-phone,per-addr,rel)

\end{tikzpicture}
\end{document}

The result is:

enter image description here

share|improve this answer
2  
"it's not available on CTAN" ... and why not?? –  Herbert Nov 17 '12 at 14:37
    
When I discovered it during a database course I search it on ctan.org/search without success: if I'm wrong please let me know and I'll edit my answer. –  Claudio Fiandrino Nov 18 '12 at 14:10
    
There is a misunderstanding. I wanted to say that I do not like it that a lot of people take a lot from CTAN but often don't give something back. –  Herbert Nov 18 '12 at 14:53
    
Oh, sorry: now I see your point :). I agree with you: the community benefit a lot when a package is on CTAN. –  Claudio Fiandrino Nov 18 '12 at 18:57
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.