A data segment is a row or column that retrieves data from a database. An expanded data segment is a row or column that can expand, so that the resulting grid expands to two or more rows or columns when viewed. Often, expanded data segments use functions such as Children Of or Descendants Of. A single data segment is a row or column that remains a single row or column when shown in the viewer.
While it is generally valid to use expanded and single data segments in the same grid, when designing a grid with large amounts of data, consider using expanded data segments rather than single data segments. Expanded data segments provide some performance advantages over single data segments; however, to produce detailed formatting on different data rows or columns, use single data segments.