Restrictions on Creating Indexes
There are certain restrictions regarding which SQL columns can be indexed. A column can only be indexed if, in its column definition fields:
- Its attribute number (field 5) is a number. Exploding attribute columns cannot be indexed (attribute number = "E"), neither can "special" columns (attribute number = "NA", "NV" or "NS").
- Its value number (field 6) is "1", "" (equivalent to "1") or "E".
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Its subvalue number (field 7) is "1", "" (equivalent to "1") or "E".
Notes:
- If the value number is "1", the subvalue number must be "1".
- If value number is "E", the subvalue number may be "1" or "E"
Refer to SQL Column and Index Definitions for details of the SQL column definition fields.