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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/unit-4.md | 2 |
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diff --git a/doc/unit-4.md b/doc/unit-4.md index 2a159ac..b5bd1ba 100644 --- a/doc/unit-4.md +++ b/doc/unit-4.md @@ -331,7 +331,7 @@ Guidelines: 6. Indexes on large values is not optimal. Try to find a smaller coded value to index to represent the larger value. 7. If the key for the index is used to determine the location where the record will be stored then a surrogate key should be used. 8. Check DBMS for limits on the # of indexes on a table. (limits include # of indexes, and size of index) -9. Be careful indexes attributes that have null values. some systems don't index `null` so sequential scan is needed for `null` value. +9. Be careful of indexing attributes that have null values. some systems don't index `null` so sequential scan is needed for `null` value. ### Designing a database for optimal query performance |