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Key Compression of Index
What is Index Compression?Oracle introduced a compression option for indexes in Oracle 8.1. You can create an index as compressed, or rebuild it to compress it.--create index with compress keyword...
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Index Scan
索引分类： Full Index Scan数据的获取仅从索引中得到，结果集按序排列（每次得到叶块中的数据都是从branch遍历到leaf block得到，顺序是以引导列为基础进行排序），索引列部分或者全部存在于...
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NOTES on concepts ---Partitions
Each partition is an independent object withits own name and optionally its own storage characteristics.Benefits include:Increased availability： The query optimizer automatically r...
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NOTES on concepts ---Tables
1. Category1) Object tables2) Relational tablesHeap-organized table Index-organized tableExternal table A table is either permanent or temporary. A permanent t...
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NOTES on concepts ---schema objects
1. Object types1) table: store data in row2) index3) partition: pieces of large tables and indexes4) view5) sequence6) dimension:A dimens...
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index-organized table
B-tree index entries are usually quite small, because they only consist of the key valueand a ROWID. In index-organized tables, however, the B-tree index entries can be large,because they consist of t...
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concept---Index-Organized Table
1. OverviewA table stored in a variation of B-tree index structure.Each index entry in the B-tree also stores non-key column values. Thus, the index is the data, the data is the index....
