\frametitle{Relation Schema}

  \begin{block}{Relation schema}
    A \textbf{relation schema} $s$ (schema of a single relation)

    \item A (finite) sequence $A_1, \dots, A_n$ of distinct \textbf{attribute names}.\\
%       \hint{The names must be distinct, i.e., $A_i \neq A_j$ for $i \neq j$.}
    \item For each attribute $A_i$ a \emph{data type} (or \textbf{domain}) $D_i$.\\
    A relation schema can be written as
        $s = (A_1:D_1, \dots, A_n:D_n)$.
  Let $\var{dom}(A_i) = \var{val}(D_i)$ be the set of possible values for $A_i$.
  \begin{exampleblock}{Creating a relation schema in SQL}
    \begin{code}{1\textwidth}{Relation schema in SQL}