先决条件 - DROP, and TRUNCATE in SQL 1. 掉落:删除是一个DDL(数据定义语言)命令,用于删除该表的表定义和索引、数据、约束、触发器等。 Performance-wise DROP 命令执行速度很快,但比 TRUNCATE 慢,因为它会引起复杂性。与 DELETE 不同,使用 DROP 命令后我们无法回滚数据。在 DROP 命令中,表空间从内存中释放...
1. Oracle中delete,truncate和drop的区别 2. 软件测试LoadRunner面试题:What is correlation? Explain the difference between automatic correlation and manu 3. 软件测试LoadRunner面试题:What is the difference between Overlay graph and Correlate graph? 4. shallow copy和deep copy的区别 5. 软件测试LoadRunner面...
在MySQL 要刪除資料可以用 DELETE 指令, 而清空資料表可以用 TRUNCATE, 刪除資料表則可以用 DROP TABLE, 以下會介紹這三個 MySQL 指令的分別。 TRUNCATE MySQL 的 TRUNCATE 是用作清空資料表, auto_increment 的數值也會重設, 清空後的資料表就如同剛建立一樣, 因為 TRUNCATE 的做法是先 DROP 掉資料表, 再用 ...
TRUNCATE MySQL 的 TRUNCATE 是用作清空资料表, auto_increment 的数值也会重设, 清空后的资料表就如同刚建立一样, 因为 TRUNCATE 的做法是先 DROP 掉资料表, 再用 CREATE 指令重新建立资料表, 删除所有资料的执行效率比 DELETE 高, 语法是: mysql> TRUNCATE TABLE table_name; 1 mysql>TRUNCATETABLEtable_name...
三者都表示删除，在需要删除数据时使用，在不再需要一张表的时候，用drop；在想删除部分数据行时候，用...
drop_Truncate_delete 一、delete 1、delete是DML,执行delete操作时,每次从表中删除一行,并且同时将该行的的删除操作记录在redo和undo表空间中以便进行回滚(rollback)和重做操作,但要注意表空间要足够大,需要手动提交(commit)操作才能生效,可以通过rollback撤消操作。 2、delete可根据条件删除表中满足条件的数据,如果不...
The DROP statement deletes the data as well as the structure. Difference between DROP and DELETE in MySQL The difference between the DROP and DELETE tables is that, after executing the DELETE statement, the contents of the table are removed, but the structure remains the same, but in the...
Difference between DELETE, TRUNCATE, and DROP Statements Let's look at the quick difference between DELETE TRUNCATE, and DROP Statements. S.No. Key Points DELETE TRUNCATE DROP 1 Classification DML (Data Manipulation Language) DDL (Data Definition Language) DDL (Data Definition Language) 2 Use...
Syntax to drop a sql table structure:DROP TABLE table_name; SQL DROP Statement Example To drop the table employee, the query would be likeDROP TABLE employee; Difference between DROP and TRUNCATE Statement:If a table is dropped, all the relationships with other tables will no longer be valid...
原文链接: 何晓东 博客最直观区别:truncate drop 是 DDL 语句,有隐式提交,不可回滚,delete 是 DML 语句,可以回滚。truncatetruncate 会删除并重新创建表...