code: public static VoltType getNumericLiteralType(VoltType vt, String value) {
          try {
              Long.parseLong(value);
          } catch (NumberFormatException e) {
              // Our DECIMAL may not be bigger/smaller enough to store the constant value
              return VoltType.DECIMAL;
          }
          return vt;
      }
docs: If the type is NUMERIC from hsqldb, VoltDB has to decide its real type.
  It's either INTEGER or DECIMAL according to the SQL Standard.
  Thanks for Hsqldb 1.9, FLOAT literal values have been handled well with E sign.
  @param vt
  @param value
  @return