将多个节点置于另一个节点下方的中心，用多个箭头连接

Question

我正在学习使用 tikz 创建图表，并希望重新创建以下内容（但文本已B*旋转）：

到目前为止我有以下内容：

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{chains}

\tikzset{
    big/.style={
        rectangle,
        rounded corners,
        draw=black, very thick,
        text width=10em,
        minimum height=3em,
        text centered,
        on chain,
        join
    },
    small/.style={
        rectangle,
        rounded corners,
        draw=black, very thick,
        text width=4em,
        minimum height=2em,
        text centered,
        on chain,
        rotate=-90,
        join
    },
    line/.style={draw, thick, <-},
    every join/.style={->, thick, shorten >=1pt},
}

\begin{document}

\begin{tikzpicture}[node distance=1.8cm, start chain=going below]
    \node[big] (A) {A};
    \node[small] (B1) {B1};
    \node[small, on chain=going right] (B2) {B2};
\end{tikzpicture}

\end{document}

但正如所见，我被困在了Bs 上。我认为链条被重定向到了正确的位置，但我不知道如何将它们置于中心位置，A同时用独特的箭头将它们连接起来。

我该如何继续？

Answer 1

像这样吗？

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{chains,calc,shapes.geometric}

\tikzset{
    big/.style={
        rectangle,
        rounded corners,
        draw=black, very thick,
        text width=10em,
        minimum height=3em,
        text centered,
        %on chain,
        %join
    },
    small/.style={
        rectangle,
        rounded corners,
        draw=black, very thick,
        text width=2em,
        minimum height=4em,
        text centered,
        on chain,
        anchor=center
    },
    line/.style={draw, thick, <-},
    every join/.style={->, thick, shorten >=1pt},
}

\begin{document}

\begin{tikzpicture}[node distance=1.8cm,>=stealth]
    \begin{scope}[start chain=going right,local bounding box=B]
    \foreach \X in {1,...,4} {\node[small] (B\X) {B\X};}
    \end{scope}
    \path let \p1=($(B.east)-(B.west)$) in 
    node[big,above=of B,minimum width=\x1](A) {A};
    \begin{scope}[start chain=going below,nodes={on chain,big,join}]
    \node[below=of B,ellipse,minimum height=5em] (C){C};
    \node (D){D};
    \end{scope}
    \foreach \X in {1,...,4} {
    \draw[line] (B\X.north) -- (B\X.north|-A.south); 
    \draw[line] (C.200-44*\X) -- (B\X.south);}
\end{tikzpicture}

\end{document}