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一、聚集索引介绍 1.什么是聚集索引？ InnoDB’s clustered indexes actually store a B-Tree index and the rows together in the same structure. 2.为什么一张表只能一个聚集索引？ When a tab 阅读全文
posted @ 2016-04-12 18:32
shamgod
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一、怎样用索引才高效 1.隔离索引列 MySQL generally can’t use indexes on columns unless the columns are isolated in the query. “Isolating” the column means it should n 阅读全文
posted @ 2016-04-12 16:38
shamgod
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一、 1. 1). Indexes reduce the amount of data the server has to examine.2). Indexes help the server avoid sorting and temporary tables.3). Indexes turn 阅读全文
posted @ 2016-04-12 11:14
shamgod
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一、 1.什么是hash index A hash index is built on a hash table and is useful only for exact lookups that use every column in the index. For each row, the st 阅读全文
posted @ 2016-04-12 10:43
shamgod
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一、 1.什么是B-Tree indexes？ The general idea of a B-Tree is that all the values are stored in order, and each leaf page is the same distance from the root 阅读全文
posted @ 2016-04-12 09:31
shamgod
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