INSERT操作在插入或更新记录时,检查到 duplicate key或者有一个被标记删除的duplicate key(本文的案例),对于普通的INSERT/UPDATE,会加LOCK_S属性锁next-key lock。而对于类似REPLACE INTO或者INSERT … ON DUPLICATE这样的SQL加的是X锁。而针对不同的索引类型也有所不同: 代码位置 ro
http://netfork.spaces.live.com/blog/cns!CB0D48877FFBC3B5!251.entry 在SQL Server 中使用DELETE和UPDATE的INNER JOIN关键字与 Access 的常规写法不同。 Access中写为: delete from t1 inner join t2 on t1.id = t2.tid 而SQL Server中须写为: delete from t1from t1inner join t2 on t1.id = t2...
-- -- SQL语句一 使用 EXISTS -- select customerid, companyname from customers as A where country = 'Spain' and not exists ( select * from orders as B where A.customerid = B.customerid ); -- -- SQL语句二 使用 IN -- select customerid, companyname from customers as A where country...
Hive的DELETE语句允许用户删除表中的特定行。这与传统的SQL数据库中的DELETE语句类似,但在Hive中有一些限制和特定的使用场景。 优势 数据清理:可以方便地删除不再需要的数据,保持数据库的整洁。 提高查询效率:删除不必要的数据可以减少查询时的I/O开销,提高查询效率。
SQL>alter session enable parallel dml; SQL> delete FROM CC.F_LOG S WHERE S.CREATE_DATE>(SYSDATE-90); 执行计划确定并行 --- | Id | Operation | --- | 0 | DELETE STATEMENT | | 1 | PX COORDINATOR | | 2 | PX SEND QC (RANDOM) | | 3 | INDEX MAINTENANCE | | 4 | PX RECEIVE...
entry_date date, job varchar(40), salary double, resume text ); 2. 查看表 查看表结构:desctabName 查看当前数据库中所有表:showtables 查看当前数据库表建表语句 showcreate tabletabName; 3. 修改表 altertable tablenameadd/modify /drop/character set/change 列名 列类型 ...
Everyone should know that DELETE is DML command and TRUNCATE is DDL command. DELETE deletes records one by one and makes an entry for each and every deletion in the transaction log, whereas TRUNCATE de-allocates pages and makes an entry for de-allocation of pages in the transaction log. ...
Namespace: Microsoft.VisualStudio.Data.Tools.Package Assembly: Microsoft.VisualStudio.Data.Tools.Package (in Microsoft.VisualStudio.Data.Tools.Package.dll)SyntaxC# Copy public static Icon DeleteEntry { get; } Property ValueType: System.Drawing..::..Icon...
Oracle Database - Enterprise Edition - Version 10.1.0.2 to 11.2.0.2 [Release 10.1 to 11.2]: ORA-32010: cannot find entry to delete in SPFILE
本示例使用Delete方法从Recordset中删除指定的记录。 Java复制 // BeginDeleteJ// The WFC class includes the ADO objects.importcom.ms.wfc.data.*;importjava.io.* ;publicclassDeleteX{// The main entry point for the application.publicstaticvoidmain(String[] args){ DeleteX(); System.exit(0); }...