Oracle 视图 ALL_CLUSTERING_JOINS 官方解释，作用，如何使用详细说明
本站中文解释
Oracle 视图 ALL_CLUSTERING_JOINS 查看多个表是否可以被组合在一起，将被聚类表对聚类索引进行多表联接，从而提高查询并行度。
使用方法：
1. 查询系统视图 ALL_CLUSTERING_JOINS：
SELECT * FROM ALL_CLUSTERING_JOINS;
2. 确定表 A、表 B 可否支持多表联接:
SELECT * FROM ALL_CLUSTERING_JOINS WHERE TABLE_NAME_$=’TabelA’ AND TABLE_NAME2= ‘TableB’;
如果查询结果不为空，则表A和表B可以进行多表联接，从而提高查询的并行度。
官方英文解释
ALL_CLUSTERING_JOINS describes joins to the dimension tables associated with tables with an attribute clustering clause the user owns or has system privileges for.
Related Views
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DBA_CLUSTERING_JOINSdescribes joins to the dimension tables associated with all tables with an attribute clustering clause in the database. -
USER_CLUSTERING_JOINSdescribes joins to the dimension tables associated with tables with an attribute clustering clause owned by the user. This view does not display theOWNERcolumn.
| Column | Datatype | NULL | Description |
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Owner of the attribute clustering table |
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Name of the attribute clustering table |
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Table 1 owner of the join |
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Table 1 name of the join |
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Table 1 column name of the join |
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Table 2 owner of the join |
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Table 2 name of the join |
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Table 2 column name of the join |
See Also:
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“DBA_CLUSTERING_JOINS”
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“USER_CLUSTERING_JOINS”
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The
ALTER TABLEsection in Oracle Database SQL
Language Reference for information about using theCLUSTERINGclause to create an attribute clustering table -
The
CREATE TABLEsection in Oracle Database SQL
Language Reference for information about using theCLUSTERINGclause to create an attribute clustering table -
Oracle Database Data
Warehousing Guide for information about dimension tables -
Oracle Database Data
Warehousing Guide for information about attribute clustering with zone maps
