Update bill_items (58 seconds); sequential scan of bill_items with a nested loop read of customer.
更新bill_items(58秒);利用对customer的嵌套循环读取,来顺序扫描bill_items。
It looks like we are doing a sequential scan (of an entire table) to satisfy the SQL command, whatever it is.
好像我们正在进行顺序扫描(对整个表)来满足SQL命令的需求,不管它是什么。
Access plan directives that force the optimizer to use the designated access method for data retrieval, either sequential scan or index scan.
访问计划指示,强制优化器使用指定的访问方法进行数据检索,要么是连续扫描,要么是索引扫描。
The above example shows that sequential scan and indexes are used to do the data retrieval, and the nested-loop join method is used to join all tables.
以上示例展示了如何使用连续扫描和索引来进行数据检索,以及如何使用嵌套循环连接方法来连接所有表。
If the inner table does not have an index, the database server will compare the cost of building an index on the table to the cost of a sequential scan, and will choose the one with the least cost.
如果内部表没有索引,那么数据库服务器就会将在表上构建索引的成本与连续扫描的成本进行比较,然后选择成本最低的那一种方法。
The experimental results showed that sequential scan ICP-AES method could be used for determining metallic and non-metallic elements in various environmental samples.
实验结果表明,顺序式扫描ICP - AES法可用于各种环境样品中金属和非金属元素的分析测定。
It is easier to describe this in detail using the explain output shown in Listing 7. Sequential scan is done on the source table, and index look-up is done on the target table.
可以很方便地利用清单7中展示的explain输出来描述其细节,可以对源表进行顺序扫描,并且在目标表上完成索引查找。
It is easier to describe this in detail using the explain output shown in Listing 7. Sequential scan is done on the source table, and index look-up is done on the target table.
可以很方便地利用清单7中展示的explain输出来描述其细节,可以对源表进行顺序扫描,并且在目标表上完成索引查找。
应用推荐