Topic: Oracle Certified Professional Exams (OCP & OCA) >> consults on the use of indexes
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| Title: consults on the use of indexes |
| electronic |
Posted: May 03, 2007 07:48:54 AM |
Total Post: 21
Joined: Feb, 2007
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The question refers if a column is candidate to be indexed or not
which tree factors would you consider while selecting the columns that will be indexed?
A) whether the columns are uses to join the table with other tables
B) the position of the columns in the table
C) whether the columns are uses in the WHERE clauses of the queries on the table
D) the cardinalities of the columns
E) whether the columns are selected in all queries or not
The answer that I don't understand is since that of the cardinalidad as I have understood if the cardinalidad is high index Bee-tree would be used and if the cardinalidad is low we would use Bitmap. |
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 fireit |
| Posted: May 04, 2007 02:10:52 PM |  |
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Total Post: 19
Joined: Apr, 2007
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if we follow this way (Bitmap for low cardinality and B Tree for high) we will conclude that all the columns must be indexed anyway. thats not true. cardinality is not an essential factor to decide wether a column must be indexed. so the question was not very clean :((
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