 This is a SQL predicate that specifies a condition on a column
      on which a free text index exists.  The expression is a
      string matching the grammar of a text search expression.
      This is computed for each evaluation of the contains predicate and
      does not have to be a constant. For example a parameter or variable
      of a containing score (e.g. procedure) is accepted. The score_limit is optional. If
      specified, it should be a numeric expression determining the minimum score
      required to produce a hit.A virtual column named @SCORE@ is available in queries
      involving a contains predicate. This can for
      example be returned in a result set or used for sorting.
      Note that the name is in upper case and is case sensitive in all
      case modes.