ERM pata de gallo en una forma agradable

Question

encontréestePublicación sobre cómo hacer diagramas ERM de pata de gallo con Tikz, pero parece extraño porque la entidad está fuera del marco. Sin embargo, funcionó.

Entonces encontréesteUna versión aún mejor e intenté combinarla, pero lamentablemente no puedo descubrir por qué no funciona. No puedo imprimir dos entidades una al lado de la otra y conectarlas con un cable de pata de gallo. Siempre se imprimen uno encima del otro...

¿Cómo puedo tener tanto las líneas como el 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 es una notación de pata de gallo para visualizar estructuras de bases de datos de TI:

Answer 1

Dado que su MWE está por encima de mi nivel de conocimiento, propongo una solución con pic( entity) con tabularinterior.

Los argumentos del picson 3: nombre del nodo, nombre de la entidad y las filas del tabular(tal vez sea más elegante tener el completo tabularcomo tercer argumento, en este caso, puedes definir dos nuevos tipos de columnas para evitar escribiéndolos todo el tiempo).

El código para elone to many , etc. se toma deuna de las publicaciones que vinculaste.

Agregué otra entidad solo para mostrar que el tamaño de la entidad varía según la cantidad de filas que coloque en el archivo 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}