In Oracle, the possibility to drop a column/columns in an existing table can be available only after the origin of oracle 8i. The column/columns in a table can be dropped either logically or physically, but most of the time we use the logic delete. And for this the "ALTER TABLE" ...
场景一:直接drop column 运行业务模拟程序,开始正常插入日志,然后删除大表的字段。 alter table t_test_col drop column vard; 影响范围: drop column操作耗时30多秒; insert 语句在drop column完成之前无法执行,等待事件为enq:TM-contention; select不受影响。 场景二:先set unused然后再drop alter table t_test_...
场景一:直接drop column 运行业务模拟程序,开始正常插入日志,然后删除大表的字段。 altertablet_test_coldropcolumn vard; 1. 影响范围: drop column操作耗时30多秒; insert 语句在drop column完成之前无法执行,等待事件为enq:TM-contention; select不受影响。 场景二:先set unused然后再drop altertablet_test_colset...
ALTERTABLEtable_nameDROP( column_name_1, column_name_2 );Code language:SQL (Structured Query Language)(sql) Oracle DROP COLUMN clause example The following statement removes theemailandphonecolumns from thesupplierstable: In this tutorial, you have learned how to use the Oracle drop column statem...
www.ibm.com|基于103个网页 2. 删除字段 起来/禁止使用,其主要目的是在业务高峰期直接删除字段(DROP COLUMN)的操作可能有风险,先暂时通过 SET UNUSED … www.net527.cn|基于38个网页 3. 删除表中的列 SQL语法与范例详解词典... ... add column 向表中添加新列 4drop column删除表中的列5 modify column...
DROP 语句将删除对象。 任何直接或间接依赖于该对象的对象都被删除或者变得不可操作。 无论何时删除对象,其描述都将从目录中删除,并且引用该对象的任何包都将失效。
Any advice/tip on how to drop the column faster? The column has only NULL values. Sorry, you can't reply to this topic. It has been closed. Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessa...
ADD COLUMN" had behaved in MySQL 8.0.28 (before MySQL 8.0.29 introduced the optimization, described in this article): Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 9 Server version: 8.0.28 Source distribution Copyright (c) 2000, 2022, Oracle and/...
ALGORITHM=INSTANT, is not supported for DROP COLUMN and it would still need a table rebuild. Welcometothe MySQL monitor. Commandsendwith;or\g. Your MySQLconnectionidis9 Server version: 8.0.28 Source distribution Copyright (c) 2000, 2022, Oracleand/orits affiliates. ...
Is there any way to bypass the problem and still store the information we need (until we want to drop it). Let’s start by taking a look at the way Oracle has used our table definition to create column definitions, just in case that gives us a clue: ...