secondary index

简明释义

辅助索引

英英释义

例句

1.Using a secondary index 二级索引 helps to quickly retrieve records based on specific attributes.

使用 secondary index 二级索引 有助于快速根据特定属性检索记录。

2.The secondary index 二级索引 allows for more efficient searches without scanning the entire table.

该 secondary index 二级索引 允许更高效的搜索，而无需扫描整个表。

3.You can create a secondary index 二级索引 on a column that is often used in WHERE clauses.

您可以在经常用于 WHERE 子句的列上创建 secondary index 二级索引。

4.When designing a database schema, consider adding a secondary index 二级索引 for frequently queried fields.

在设计数据库架构时，考虑为经常查询的字段添加 secondary index 二级索引。

5.In a database, a secondary index 二级索引 can speed up query performance for non-primary key columns.

在数据库中，secondary index 二级索引 可以加快非主键列的查询性能。

作文

In the field of database management, the concept of a secondary index plays a crucial role in enhancing data retrieval efficiency. A secondary index is an additional data structure that provides an alternative way to access records in a database table, apart from the primary key. This can significantly speed up query performance, especially when dealing with large datasets where searching through a primary key alone may not be efficient. For instance, consider a scenario where a company has a database of employees, and the primary key is the employee ID. If a manager frequently needs to retrieve employee information based on their last names, creating a secondary index on the last name column would allow for faster searches. Instead of scanning the entire employee table, the database can utilize the secondary index to quickly locate the relevant records. However, while secondary indexes offer significant advantages in terms of query performance, they also come with trade-offs. Each secondary index requires additional storage space and can slow down data modification operations, such as INSERT, UPDATE, or DELETE. This is because the database must maintain the integrity of all indexes whenever data is changed. Therefore, it is essential for database designers to carefully evaluate the need for secondary indexes and to strike a balance between read and write performance. Moreover, the effectiveness of a secondary index largely depends on the specific queries being executed. If a query frequently filters or sorts data by a certain attribute, it is wise to create a secondary index on that attribute. Conversely, if an attribute is rarely used in queries, having a secondary index on that attribute may not provide significant benefits. In summary, understanding the role of secondary indexes is vital for anyone involved in database management. They serve as powerful tools for optimizing data retrieval, allowing for quicker access to records based on non-primary key attributes. However, the decision to implement a secondary index should be made judiciously, considering both the advantages and the potential downsides. By strategically utilizing secondary indexes, organizations can improve their database performance and ensure that they are able to efficiently handle the growing volumes of data in today's digital landscape.

在数据库管理领域，secondary index的概念在提高数据检索效率方面起着至关重要的作用。secondary index是一个额外的数据结构，提供了一种访问数据库表中记录的替代方式，除了主键之外。这可以显著加快查询性能，特别是在处理大型数据集时，仅通过主键进行搜索可能效率不高。例如，考虑一个场景，一个公司拥有员工数据库，主键是员工ID。如果经理经常需要根据姓氏检索员工信息，那么在姓氏列上创建一个secondary index将允许更快速的搜索。数据库可以利用secondary index快速定位相关记录，而不是扫描整个员工表。然而，虽然secondary indexes在查询性能方面提供了显著的优势，但它们也带来了权衡。每个secondary index需要额外的存储空间，并且可能会减慢数据修改操作，例如INSERT、UPDATE或DELETE。这是因为数据库必须在数据更改时维护所有索引的完整性。因此，数据库设计者必须仔细评估secondary indexes的需求，并在读取和写入性能之间找到平衡。此外，secondary index的有效性在很大程度上取决于执行的特定查询。如果一个查询经常按某个属性过滤或排序数据，那么在该属性上创建secondary index是明智的。相反，如果一个属性在查询中很少使用，那么在该属性上拥有secondary index可能不会提供显著的好处。总之，理解secondary indexes的作用对于任何参与数据库管理的人来说都是至关重要的。它们作为优化数据检索的强大工具，允许基于非主键属性更快地访问记录。然而，实施secondary index的决定应该谨慎做出，考虑到优点和潜在的缺点。通过战略性地利用secondary indexes，组织可以改善其数据库性能，并确保能够有效处理当今数字环境中不断增长的数据量。