Complex Field Names

Some field names returned by SQL may be invalid as Vortex variable names. For example, an embedded Texis function call such as:

  <SQL "select Title, text2mm(Text) from books where id = $id">
  </SQL>

would attempt to return the fields Title and text2mm(Text) as Vortex variables. However, ``text2mm(Text)'' is not a valid Vortex name. Such invalid fields are silently discarded by Vortex; in order to return them they must be renamed in the SQL statement:

  <SQL "select Title, text2mm(Text) result from books
        where id = $id">
  </SQL>

The text2mm(Text) field is here renamed to result, a valid Vortex variable name.

Another common example is the $rank value set for each value in a likep query. The ``$'' is part of the actual SQL field name. In Vortex however, it must be escaped, and the field renamed:

  <SQL "select $$rank Rank, Title from books
        where Title likep 'Norway fjords'">
    ...
  </SQL>

The rank value is here returned in the Vortex variable $Rank.