系统依据属性的类型决定是否要基于此属性创建非主键索引、是否要保存此非主键索引。
The system determines whether it needs establishing and reserving the non-primary index by the classification of the attribute.
为了更好地解释说明基数估计值的提高，撤销除主键索引外的所有employee表上的现有索引。
To better illustrate the improvement in cardinality estimation, drop all the existing indexes on the EMPLOYEE table except the primary key index.
在分析了用于查找内存数据的非主键索引的特性之后，设计并实现了一个适合于内存数据库的非主键索引机制。
After analyzing the characteristics of the non-primary index used to search the data in the main memory, a new non-primary index system is designed and implemented which fits to MMDB.
这就是Hypertable发挥作用的地方，它提供了一种可伸缩的解决方案来存储经过主键索引的数据，并且可以在线查询。
This is where Hypertable enters the picture. It provides a scalable solution to store data indexed by a primary key that can be queried online.
它将查询数据库，为结果的每行中的每列建立索引，并且将每个索引条目绑定到行的主键上。
It queries your database, indexes each column in each row of the result, and ties each index entry to the row's primary key.
此外，在DB 2中创建复制之前，您会希望保证每一个数据库表都具有一个主键或惟一索引。
Also, before setting up replication in DB2, you will want to ensure that every database table has a primary key or unique index.
当定义一个主键约束时，联邦系统自动创建一个惟一的索引规范。
When a primary key constraint is defined, the federated system automatically creates a unique index specification.
然而，DB 2复制要求使用一个主键或惟一索引来区分一个表中的记录。
However, DB2 replication requires a key or index to uniquely identify rows in a table.
其原因是：规范化需要更多的表，连接等操作，主键、索引，从而需要更多的内部操作。
The reason: Normalization requires more tables, table joins, keys and indexes and thus more internal database operations for implement queries.
ccd表中必须有惟一性约束——可以通过主键或者源表或ccd表上的惟一索引实现。
Uniqueness in the CCD table must be enforced — either by a primary key or unique index on the source table or CCD table.
sql _ query必须包括后续查找需要使用的主键，并且它必须包括需要索引和用作组的所有字段。
The sql_query must include the primary key you want to use for subsequent lookups, and it must include all the fields you want to index and use as groups.
这两个数据库系统都支持主键，以及支持加速查询和约束输入的键索引。
The two database systems support primary keys, along with key indices that allow you to speed up queries and constrain input.
全部主键和外键均定义了索引，来支持12个表之间有效的结合。
Indexes are defined on all primary and foreign key columns to support efficient joins between the 12 tables.
换句话说，作为分区键一部分的所有列都必须出现在主键或惟一索引定义中。
In other words, all columns that are part of the partitioning key must be present in the primary key or unique index definition.
为基于主键、外键和索引的通用查询提供访问
Provides access to common queries based on primary keys, foreign keys, and indexes.
我们只保留了一个组合主键和一个辅助索引来完成所有的查询。
We keep only a compound primary key and a secondary index for each row, and answer all queries from a single index.
索引扫描实际上是对父表进行主键查找，并完成外键约束验证。
The latter is actually a primary key lookup against the parent table and constitutes the foreign key constraint verification.
表的主键和所有惟一索引都必须是相关分区键的超集。
The primary key and any unique index of the table must be a superset of the associated partitioning key.
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。
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.
该索引要求主键的每一个值都必须是唯一的。
This index requires each value in the primary key to be unique.
主键列、外键列和索引上使用的列的数据类型。
Data type of primary key columns, foreign key columns, and columns used on indexes.
创建了表、主键、外键，和索引。
Created the tables, primary keys, foreign keys, and indexes.
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。
The new table 'test'. '_online_table_new' does not have a PRIMARY KEY or a unique index which is required for the DELETE trigger.
为什么我们通常在删除主键创建索引？
Why do we usually create an index before dropping the primary key?
表必须具有相同的主键、唯一索引或唯一约束。
Tables must have the same primary key, unique index, or unique constraint.
如果要更改列顺序、索引名称、聚集选项或填充因子，则要修改主键。
Modify a primary key if you want to change the column order, index name, clustered option, or fill factor.
如果源表不包含主键或聚簇的索引，该工具可以自动添加rowid列和列上的聚集的索引设置转换过程中。
If the source table doesn't include a primary key or clustered index, the tool can automatically add a ROWID column and set the clustered index on the column during the conversion.
建议优化的时候，加上主键和索引，查询效率会提高。
Recommendations to optimize the time, together with the primary key and index, query efficiency will improve.
建议优化的时候，加上主键和索引，查询效率会提高。
Recommendations to optimize the time, together with the primary key and index, query efficiency will improve.
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