0oracle對(duì)象定義-概念(45)(編輯修改稿)
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【文章內(nèi)容簡(jiǎn)介】 2 XYZ ORDER TABLE Copyright 169。 2023 Global Business Solutions, Inc. Balanced Index Tree (B*Tree) 0 0000 2023 4000 0000 2023 2023 2499 3000 3001 4001 4999 5000 7000 9000 5000 5999 7000 7200 8100 9000 9999 ROWID|1/4” Rolled Sheet|100 Feet|5 Days|. Copyright 169。 2023 Global Business Solutions, Inc. Bitmap Index ? Bitmap created for each column value ? Common Usage ? Very Large Tables ? LowCardinality Columns ? Features ? Requires minimal storage ? Improves performance ‘ F’ BILL LISA ANN TED 1 0 0 1 0 1 1 0 ‘ M’ Copyright 169。 2023 Global Business Solutions, Inc. Function Based Index ? Create on functions or expressions ? User generated PL/SQL ? SQL functions (nonaggregate) ? External program (C callout) SQL SELECT salary, salary* FROM employees。 Copyright 169。 2023 Global Business Solutions, Inc. Partition Data ? Depose tables and indexes ? Each partition can be stored in different tablespace Copyright 169。 2023 Global Business Solutions, Inc. Advantages of Partitions ? Reduce time for data loads and index creation ? Increase availability of missioncritical databases ? Create partition independence ? Enable concurrent operations on separate partitions ? Execute queries on partitions instead of full table scan Copyright 169。 2023 Global Business Solutions, Inc. Advantages of Partitions ? Control data storage across physical devices ? Maintain partition transparency ? Programs do not need to reference partitions ? Programs can take advantage of partitions Copyright 169。 2023 Global Business Solutions, Inc. Equipartitions ? Database objects have same logical partitions ? Examples ? Master and detail table ? Table and index Copyright 169。 2023 Global Business Solutions, Inc. Global Partitioned Indexes ? Can improve performance ? Can contain keys from all partitions of corresponding table Copyright 169。 2023 Global Business Solutions, Inc. Index Organized Tables ? Data stored with B*Tree index ? Table must have primary key, which acts as index ? Appropriate for plex or unstructured data ? Spatial ? OLAP Data Data Data 9000 9999 Data Data Data Data Data Data 3001 4001 4999 0 0000 2023 4000 Data Data Data 50
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