16. The new table 'test'. '_online_table_new' does not have a PRIMARY KEY or a uniqueindex which is required for the DELETE trigger.
原表需要一个主键或则唯一索引，因为删除的触发器需要，否则数据不会被复制。
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17. Similarly, you cannot create a uniqueindex on multiple columns if the combination of columns contains NULL in more than one row.
同样地，如果一个以上的资料列中的一组资料行全为NULL的话，您将无法在该组资料行上建立唯一索引。
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18. An index specification that defines a uniqueindex also conveys information about the uniqueness of the index columns to the federated system.
定义惟一索引的索引规范还将关于索引列惟一性的信息传递给联邦系统。
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19. From the performance perspective, this is considered a very efficient join operation, because the cost for scanning the inner table is optimal via unique access through a uniqueindex.
20. However, if the session data conflicts with a new index, (such as duplicate rows conflicting with a uniqueindex), the index is not materialized for that session until the data is corrected.
21. It then encrypts the index using a searchable encryption scheme and encrypts the unique key with an attribute-based encryption scheme under an appropriate policy.
然后它会使用可搜索的加密模式对索引进行加密，用基于属性的加密模式以恰当的手段对唯一密钥加密。
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22. For indexes that are not unique, the number of index keys is less than the number of records.
对于那些不是唯一的索引，索引键的数量要少于记录的数量。
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23. The table is logically joined to itself, and the more selective non-leading index keys are applied as index bound filters to each unique combination of the leading key values.
24. However, since XML columns cannot be part of the table partitioning key, any unique XML values index will have to be created as a global index.
然而，由于xml列不属于表分区键的一部分，任何唯一xml值索引必须创建为全局索引。
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25. Ideally, every key value in the index is unique.
理想情况是，索引中的每个键值都是惟一的。
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26. Many repositories have unique ways of storing native content and metadata. OmniFind, for example, does not actually store the native content for an item in its index.
27. The reason for this is that the other tables in the DB2 UDB SAMPLE database have no primary key, and hence no index information to associate a unique ECO key with.
原因是DB2UDBSAMPLE数据库中的其他表没有主键，因此没有索引信息可以关联惟一的ECO 键。
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28. Assign each LPAR a unique GUID index within each physical computer to distinguish the different LPARs using InfiniBand.
29. A primary index is a unique feature of Teradata's database - it offers the benefit of an index without the traditional overhead associated with an index.
主索引是teradata数据库的惟一特性—在避免索引相关额外开销的情况下提供索引的优势。
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30. Because the partno field is declared unique, repeated upload operations of the same part number merely replace the old index record with a new record.
