truncate statement in sql

Degree from strong to weak 1, drop table TB drop directly delete the form, no way back 2, truncate (table) TB Delete all data in the table, cannot be used with where 3, delete from TB (where) Delete data in a table (can make a row) difference: Truncate and delete difference 1, transaction: Truncate is not rollback, but delete can rollback; Reason:

, environment, and plot are essential.The example is the most vivid and can best illustrate the problem. Therefore, it is useless to go to the topic directly. According to the preceding syntax structure, to delete all records whose user_name is simaopig in the firends table, you can use the following SQL statement:Delete from friends where user_name = 'simaopig ';Delete considerations:From the syntax structure, we can see that, like the update

Label:1. Delete: Delete rows from the datasheet (you can delete a row or delete all rows without deleting the data table)Delete a row: Delete from data table name where column name = value;Delete all rows: Delete*from data table name2. Drop: Delete a datasheet or database or table fieldDelete database: Drop database nameDelete a data table (the structure, properties, and indexes of the table are also deleted): Use database namedrop table data table 1 name, data table 2 nameDelete a data table fi

watermark (back to the original).4. Efficiency: Drop > Truncate > Delete5. Security: Careful use of drop and truncate, especially when there is no backup, want to delete some data can use delete need to take WHERE clause, rollback segment is big enough, want to delete table can use drop, want to keep table just want to delete all the data of the table, If you have nothing to do with things you can use

Recently encountered a problem in the project, and the current affairs of updating expired data were not rolled back. The transaction configuration was carefully checked before and after, and the problem was not found. Final steps Recently encountered a problem in the project, and the current affairs of updating expired data were not rolled back. The transaction configuration was carefully checked before and after, and the problem was not found. Final steps Recently encountered a problem

Label:a), First of all, let's say the error phenomenon: Most of the popular Ecshop templates on the market need to execute a paragraph or a few SQL statements to modify the data structure or initialize some of it. Most Ecshop administrators will execute these SQL statements through the Ecshop backend database management SQL query for the sake of convenience. The

Tags: horizontal return rom reason back cat rollback where deleteUsage:1. DROP table TBDrop will delete the table directly, there is no way to retrieve2, truncate (table) TBDelete all data in a table and cannot be used with where3. Delete from TB (where)Delete data from a table (you can make a row)The difference between truncate and delete1, Business: Truncate is

statement without a WHERE clause: Both delete all rows in the table. However, TRUNCATE TABLE is faster than DELETE and uses less system and transaction log resources. The DELETE statement deletes one row at a time and records an entry in the transaction log for each row that is deleted. TRUNCATE table deletes data by

statement without a WHERE clause: Both delete all rows in the table. However, TRUNCATE TABLE is faster than DELETE and uses less system and transaction log resources. The DELETE statement deletes one row at a time and records an entry in the transaction log for each row that is deleted. TRUNCATE table deletes data by

, and the high waterline (W2atermark) remains in its original position.apparently the drop statement frees all the space occupied by the table.The truncate statement frees space to minextents extent by default unless reuse storage is used; Truncate will reset the high watermark (back to the beginning). 4. Speed, in ge

The similarities between the three commands: truncate and delete without the where clause, and drop will delete the data in the table. The difference is that truncate will clear the table data table and set the id to start from 1, delete: only records are deleted. drop can be used to delete tables or databases and release all the space occupied by tables. The similarities between the three commands:

statement instead of truncate or to disable CDC first and then enable the CDC on the table after the truncate operation is completed. I am interested to know if you have any interesting fact of above CDC. I will publish the information on this blog with due credit. Reference:Pinal Dave (Http://blog.SQLAuthority.com) There is also an article. Http://ww

The similarities between the three commands: truncate and delete without the where clause, and drop will delete the data in the table. The difference is that truncate will clear the table data table and set the id to start from 1, delete: only records are deleted. drop can be used to delete tables or databases and release all the space occupied by tables. Differences:1.

Different points:1. Truncate and delete Delete only the data do not delete the structure of the table (definition)The DROP statement deletes the table's structure-dependent constraints (constrain), triggers (trigger), indexes (index); Stored procedures/functions that depend on the table are preserved, but become invalid states. The code is as follows Copy Code

Tags: from delete SQL statement PAC Database operation table Apple Div convertFirst, syntax in SQL 1, drop TableNBSP; table name eg:drop table dbo. Sys_test 2, truncate tableNBSP; Table name eg:truncate table dbo. sys_test 3, delete from table name NBSP; where Column name = value eg:delete from dbo.

-----DeleteHaunt occasions: Delete Table TB-although it is also the data to delete the entire table, but the process is painful (the system is deleted on one line, efficiency is lower than truncate)OrDelete Table TB Where conditionTrick: delete Content does not delete the definition, does not free space. One of the three brothers is the most easily bullied.And then the delete is not explained in detail, and we all know it.A small summary of truncate:T