label next to an arrow

Question

I am trying to place a label next to the thick arrow between the first and the second box in this figure. My minimal code to generate the figure (sans the label) is the following. I am not sure how to put the label next to the arrow:

\documentclass{scrartcl}        % KOMA script (my preference)

\usepackage{tikz}
\usetikzlibrary{shapes,shapes.multipart,fit,backgrounds,arrows}

\begin{document}
\begin{tikzpicture}
\tikzstyle{bigbox} = [minimum width=5cm, minimum height=3.8cm,draw, thick, rectangle,fill=blue!20,fill opacity=0.3]
\tikzstyle{box} = [text width=4cm,text height=3mm,rectangle,draw,blue!50,fill=blue!50,text=white]

\node[box,align=center] (B1) {View Query Repository};
\node[box,below of=B1,yshift=-0.75cm,align=center] (B2) {ViewDF Repository};
\node[box,below of=B2,yshift=-0.75cm,align=center] (B3) {View Maintainer};

\draw[-triangle 90, line width=1mm, blue!50,postaction={draw=blue!50, line width=3mm, shorten >=0.2cm, -}](B1.south) -- (B2.north);
\draw[<->,>=triangle 90, line width=1mm, blue!50,postaction={draw=blue!50, line width=3mm, shorten >=0.2cm,shorten <=0.2cm, -}](B2.south) -- (B3.north);

\node[bigbox] [fit = (B1) (B3)] (box1) {};

\end{tikzpicture}
\end{document}