High_Non_Group (HNG) Index

Add an HNG index for range searches.

An HNG index requires approximately three times less disk space than an HG index. On that basis alone, if you do not need to do group operations, use an HNG index instead of an HG index.

Conversely, if you know you are going to do queries that a HG index handles more efficiently, or if the column is part of a join, or you want to enforce uniqueness, use an HG index.

• Recommended Use of HNG
  The HNG index is not recommended for GROUP BY queries..
• Advantages and Disadvantages of High_Non_Group
  High_Non_Group indexes have advantages and disadvantages.
• Comparison to Other Indexes
  A comparison of the HNG index to similar indexes.
• Additional Indexes for HNG Columns
  The High_Group index is also appropriate for an HNG column.