An index kept apart from the rows themselves, storing key values plus pointers back to each row. Whereas a table has only one clustered index, it can carry many of these.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains Nonclustered index in context, with comparison tables and the common traps.
Terms in this definition
- Index
Speeds up queries that filter on certain columns by keeping those columns sorted, with pointers back to each row; the price is more storage and slower writes.
- Index field attributes
Settings applied to each field in an Azure AI Search index:
searchablefor full text,retrievableto return it,filterablefor exact-match$filter,sortable,facetablefor counts, andkeyfor the unique document ID. - VALUES
Returns in DAX the distinct column values, or table rows, still visible after filters are applied, sometimes with an extra blank entry. CALCULATE often takes the result as a table filter.
- Event
Table in Log Analytics where entries from Windows event logs are kept.
Related terms
- Heap
A table without a clustered index. Its rows are kept in no particular order, and any nonclustered index locates them by row identifier (RID).
- Included column
A column that isn't part of an index's key but is stored at its bottom (leaf) level, added using INCLUDE so that a nonclustered index covers more queries. These extra columns aren't counted against key size or key-column limits.