作者：Fuckkkkkkkkkk7777_352 | 来源：互联网 | 2018-07-11 12:21
IndexingRulesofThumb:Indexeveryprimarykeyandmostforeignkeysinthedatabase.AttributesfrequentlyreferencedinSQLWHEREclausesarepotentiallygoodcandidatesforanindex.UseaB+treeindexforbothequalityandrangequer
Indexing Rules of Thumb : Index every primary key and most foreign keys in the database. Attributes frequently referenced in SQL WHERE clauses are potentially good candidates for an index. Use a B+tree index for bothequality and range quer
Indexing Rules of Thumb :
Index every primary key and most foreign keys in the database.
Attributes frequently referenced in SQL WHERE clauses are potentially
good candidates for an index.
Use a B+tree index for both
equality and range queries.
Choose carefully one clustered
index for each table.
Avoid or remove redundant
indexes.
Add indexes only when
absolutely necessary.
Add or delete index columns for
composite indexes to improve performance.
Do not alter primary key columns.
Use attributes for indexes with
caution when they are frequently updated.
Keep up index maintenance on a
regular basis; drop indexes only when
they are clearly hurting performance.
Avoid extremes in index cardinality and value distribution.
Covering indexes (index only) are useful, but often overused.
Use bitmap indexes for high-volume data, especially in data
warehouses.
Index Selection Decisions :
Does this table require an index or not, and if so which search
key should I build an index on?
When do I need multi-attribute
(composite) search keys, and
which ones should I choose?
Should I use
a dense or sparse index?
When can I use a covering
index?
Should I create a clustered
index?
Is an index still preferred
when updates are taken into
account? What are the tradeoffs between queries and updates for each index
chosen?
How do I know I made the right
indexing choice?
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