Pé de galinha ERM de um jeito legal

Question

eu encontreiessepost sobre como fazer diagramas ERM de pé de galinha com Tikz, mas parece estranho porque a entidade está fora do quadro. No entanto, funcionou.

Então eu encontreiesseversão ainda melhor e tentei combiná-la, mas infelizmente não consigo descobrir por que não funciona. Não consigo imprimir duas entidades lado a lado e conectá-las com um fio de pé de galinha. Eles sempre imprimem um sobre o outro...

Como posso ter as linhas e o estilo?

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{shapes.multipart}
\usetikzlibrary{matrix}
\usetikzlibrary{positioning}
\usetikzlibrary{shadows}
\usetikzlibrary{calc}

\tikzset{
    entity/.code={
        \tikzset{
            rounded corners,             
            name=#1,
            inner sep=2pt,
            every entity/.try,
        }%
        \def\entityname{#1}%
    },
    entity anchor/.style={matrix anchor=#1},
    every entity/.style={
            draw,
    },
    every property/.style={
        inner xsep=0.20cm, inner ysep=0.075cm, anchor=west, text width=1.75in
    }
}
\def\property#1{\node[name=\entityname-#1, every property/.try]{\propertysplit#1;};}
\def\properties{\begingroup\catcode`\_=11\relax\processproperties}
\def\processproperties#1{\endgroup%
    \gdef\propertycode{}%
    \foreach \p in {#1}{%
    \expandafter\expandafter\expandafter\gdef\expandafter\expandafter\expandafter\propertycode%
            \expandafter\expandafter\expandafter{\expandafter\propertycode\expandafter\property\expandafter{\p}\\}%
    }%
    \propertycode%
}
\def\propertysplit#1:#2;{#1:\hfill#2}

\def\entitynamenode{%
\node[every entity name/.try] (\entityname-name) {\entityname};
\draw (\entityname-name.south west) -- (\entityname-name.south east);
\\[1ex]
}
\tikzset{
  every entity name/.style={every property/.try, align=center}
}
\begin{document}
\begin{tikzpicture}[every node/.style={font=\ttfamily}, node distance=0.5in]
\matrix (m1) [entity=Employee] {
    \entitynamenode
    \properties{
        Username:,
        Password :  varchar(255),        
        Name :  varchar(255),
        LastName :  varchar(255)
    }
};
\matrix (m2) [entity=Student] {
    \entitynamenode
    \properties{
        Username:,
        Password :  varchar(255),        
        Name :  varchar(255),
        LastName :  varchar(255)
    }
};
\draw [->] (m1) -- (m2); % <-- it break's here...
%\draw [one to omany] (Employee-Username:) to node[above]{label} (Student-Username:);
\end{tikzpicture}
\end{document} 

Editar: esta é uma notação de pé de galinha para visualizar estruturas de banco de dados de TI:

Answer 1

Como o seu MWE está acima do meu nível de conhecimento, proponho uma solução com um pic( entity) com tabularinterior.

Os argumentos do picsão 3: nome do nó, nome da entidade e as linhas do tabular(talvez seja mais elegante ter o completo tabularcomo terceiro argumento, neste caso, você pode definir dois novos tipos de coluna para evitar digitando-os o tempo todo).

O código para one to many, etc. é retirado deuma das postagens que você vinculou.

Adicionei outra entidade apenas para mostrar que o tamanho da entidade varia de acordo com o número de linhas que você coloca no arquivo tabular.

\documentclass{article}
\usepackage{array}
\renewcommand{\arraystretch}{1.1}
\usepackage{tikz}
\usetikzlibrary{shapes.multipart}
\usetikzlibrary{positioning}
\usetikzlibrary{shadows}
\usetikzlibrary{calc}

% code for "one to omany", etc. is taken from https://tex.stackexchange.com/q/141797/101651
\makeatletter
\pgfarrowsdeclare{crow's foot}{crow's foot}
{
    \pgfarrowsleftextend{+-.5\pgflinewidth}%
    \pgfarrowsrightextend{+.5\pgflinewidth}%
}
{
    \pgfutil@tempdima=0.6pt%
    %\advance\pgfutil@tempdima by.25\pgflinewidth%
    \pgfsetdash{}{+0pt}%
    \pgfsetmiterjoin%
    \pgfpathmoveto{\pgfqpoint{0pt}{-9\pgfutil@tempdima}}%
    \pgfpathlineto{\pgfqpoint{-13\pgfutil@tempdima}{0pt}}%
    \pgfpathlineto{\pgfqpoint{0pt}{9\pgfutil@tempdima}}%
    \pgfpathmoveto{\pgfqpoint{0\pgfutil@tempdima}{0\pgfutil@tempdima}}%
    \pgfpathmoveto{\pgfqpoint{-8pt}{-6pt}}% 
    \pgfpathlineto{\pgfqpoint{-8pt}{-6pt}}%  
    \pgfpathlineto{\pgfqpoint{-8pt}{6pt}}% 
    \pgfusepathqstroke%
}

\pgfarrowsdeclare{omany}{omany}
{
    \pgfarrowsleftextend{+-.5\pgflinewidth}%
    \pgfarrowsrightextend{+.5\pgflinewidth}%
}
{
    \pgfutil@tempdima=0.6pt%
    %\advance\pgfutil@tempdima by.25\pgflinewidth%
    \pgfsetdash{}{+0pt}%
    \pgfsetmiterjoin%
    \pgfpathmoveto{\pgfqpoint{0pt}{-9\pgfutil@tempdima}}%
    \pgfpathlineto{\pgfqpoint{-13\pgfutil@tempdima}{0pt}}%
    \pgfpathlineto{\pgfqpoint{0pt}{9\pgfutil@tempdima}}%
    \pgfpathmoveto{\pgfqpoint{0\pgfutil@tempdima}{0\pgfutil@tempdima}}%  
    \pgfpathmoveto{\pgfqpoint{0\pgfutil@tempdima}{0\pgfutil@tempdima}}%
    \pgfpathmoveto{\pgfqpoint{-6pt}{-6pt}}% 
    \pgfpathcircle{\pgfpoint{-11.5pt}{0}} {3.5pt}
    \pgfusepathqstroke%
}

\pgfarrowsdeclare{one}{one}
{
    \pgfarrowsleftextend{+-.5\pgflinewidth}%
    \pgfarrowsrightextend{+.5\pgflinewidth}%
}
{
    \pgfutil@tempdima=0.6pt%
    %\advance\pgfutil@tempdima by.25\pgflinewidth%
    \pgfsetdash{}{+0pt}%
    \pgfsetmiterjoin%
    \pgfpathmoveto{\pgfqpoint{0\pgfutil@tempdima}{0\pgfutil@tempdima}}%
    \pgfpathmoveto{\pgfqpoint{-6pt}{-6pt}}% 
    \pgfpathlineto{\pgfqpoint{-6pt}{-6pt}}%  
    \pgfpathlineto{\pgfqpoint{-6pt}{6pt}}% 
    \pgfpathmoveto{\pgfqpoint{0\pgfutil@tempdima}{0\pgfutil@tempdima}}%
    \pgfpathmoveto{\pgfqpoint{-8pt}{-6pt}}% 
    \pgfpathlineto{\pgfqpoint{-8pt}{-6pt}}%  
    \pgfpathlineto{\pgfqpoint{-8pt}{6pt}}%    
    \pgfusepathqstroke%
}
\makeatother

\tikzset{%
    pics/entity/.style n args={3}{code={%
            \node[draw, blue,
            shade, top color=white, bottom color=blue!30,
            drop shadow={gray!70,
                shadow xshift=3pt,
                shadow yshift=-3pt,
                rounded corners},  
            rounded corners,  
            font=\ttfamily\footnotesize, 
            rectangle
            ] (#1)
            {\color{black}\begin{tabular}{>{\raggedright\arraybackslash}p{4.5em}>{\raggedleft\arraybackslash}p{6em}}
                    #3
                \end{tabular}
            };%
            \node[font=\ttfamily\footnotesize,
            text height=1.5ex,text depth=.25ex,
            above =0pt of #1
            ] 
            {#2};%
    }},
    pics/entitysimple/.style n args={3}{code={%
            \node[draw, rounded corners,             
            rectangle split,
            rectangle split parts=2,
            font=\ttfamily\footnotesize,
            text height=1.5ex,text depth=.25ex
            ] (#1)
            {#2 \nodepart{second} 
                \begin{tabular}{>{\raggedright\arraybackslash}p{4.5em}>{\raggedleft\arraybackslash}p{6em}}
                    #3
                \end{tabular}
            };%
    }},
    zig zag to/.style={
        to path={(\tikztostart) -| ($(\tikztostart)!#1!(\tikztotarget)$) |- (\tikztotarget)}
    },
    zig zag to/.default=0.5,   
    one to one/.style={
        one-one, zig zag to
    },    
    one to many/.style={
        one-crow's foot, zig zag to,
    },
    one to omany/.style={
        one-omany, zig zag to
    },      
    many to one/.style={
        crow's foot-one, zig zag to
    },
    many to many/.style={
        crow's foot-crow's foot, zig zag to
    }, 
}
\begin{document}
    \noindent Version like your colored image:
    \begin{center}
        \begin{tikzpicture}
        \pic {entity={empl}{Employee}{%
                Username: & \textcolor{red}{(PK)} \\
                Password: & varchar(255) \\        
                Name: & varchar(255) \\
                LastName: & varchar(255) \\ 
        }};
        \pic[right=7em of empl] {entity={stud}{Student}{%
                Username: & \textcolor{red}{(PK)} \\
                Password: & varchar(255) \\        
                Name: & varchar(255) \\
                LastName: & varchar(255) \\ 
        }};
        \pic[below=12ex of stud] {entity={thesis}{Thesis}{%
                Title: & \textcolor{red}{(PK)} \\
                Year: & numeric(4) \\        
        }};
        \draw[one to omany] ($(empl.north east)-(0,10pt)$) -- node[above]{\footnotesize\texttt{teaches}} ($(stud.north west)-(0,10pt)$);
        \draw[one to one] ($(stud.south)+(50pt,0)$) -- node[left]{\footnotesize\texttt{writes}} ($(thesis.north)+(50pt,0)$);
        \draw[one to many] ($(empl.south)+(30pt,0)$) |- node[left, yshift=36pt] {\footnotesize\texttt{supervises}} ($(thesis.west)+(0,4pt)$);
        \end{tikzpicture}
    \end{center}
    Version like your code:
    \begin{center}
        \begin{tikzpicture}
        \pic {entitysimple={empl}{Employee}{%
                Username: & \textcolor{red}{(PK)} \\
                Password: & varchar(255) \\        
                Name: & varchar(255) \\
                LastName: & varchar(255) \\ 
        }};
        \pic[right=7em of empl] {entitysimple={stud}{Student}{%
                Username: & \textcolor{red}{(PK)} \\
                Password: & varchar(255) \\        
                Name: & varchar(255) \\
                LastName: & varchar(255) \\ 
        }};
        \pic[below=12ex of stud] {entitysimple={thesis}{Thesis}{%
                Title: & \textcolor{red}{(PK)} \\
                Year: & numeric(4) \\        
        }};
        \draw[one to omany] (empl.east) -- node[above]{\footnotesize\texttt{teaches}} (stud.west);
        \draw[one to one] (stud.south) -- node[left]{\footnotesize\texttt{writes}} (thesis.north);
        \draw[one to many] (empl.south) |- node[left, yshift=44pt, xshift=-2pt] {\footnotesize\texttt{supervises}} (thesis.west);
        \end{tikzpicture}
    \end{center}        
\end{document}