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When increasing the size of VARCHAR column on a large table could there be any problems?
...er 2008 and I need to make a VARCHAR field bigger, from (200 to 1200) on a table with about 500k rows. What I need to know is if there are any issues I have not considered.
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Difference Between Schema / Database in MySQL
...racle Database product, a schema represents only a part of a database: the tables and other objects owned by a single user.
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Google Chrome Printing Page Breaks
...g to spec break-after and break-before apply only to block-level elements, table row groups, table rows (but see prose): drafts.csswg.org/css-break-3/#break-between – that means no floats or any fancy positioning tricks.
– Mikko Rantalainen
Jun 2 '16 at 11:27...
PostgreSQL - how to quickly drop a user with existing privileges
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Doing: CREATE TABLE foo(bar SERIAL); ALTER TABLE foo OWNER TO postgres; CREATE USER testuser; GRANT ALL ON foo TO testuser; DROP USER testuser gave the error messages: ERROR: role "testuser" cannot be dropped because some objects depend...
How to create materialized views in SQL Server?
...ually I want to create a view and it should update automatically when base tables are changed. Can anyone explain with an query example..
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When and why are database joins expensive?
...nality when (if) they set up indexes.
It is important to understand that table scans (examination of every row in a table in the course of producing a join) are rare in practice. A query optimiser will choose a table scan only when one or more of the following holds.
There are fewer than 200 row...
Split comma-separated strings in a column into separate rows
...approach but modified according to Rich Scriven's comment,
Jaap's two data.table methods and two dplyr / tidyr approaches,
Ananda's splitstackshapesolution,
and two additional variants of Jaap's data.table methods.
Overall 8 different methods were benchmarked on 6 different sizes of data frames u...
Oracle find a constraint
...stem generated constraint name. For instance, if we specify NOT NULL in a table declaration. Or indeed a primary or unique key. For example:
SQL> create table t23 (id number not null primary key)
2 /
Table created.
SQL> select constraint_name, constraint_type
2 from user_constraint...
MySQL 启动报错 Table \'mysql.plugin\' doesn\'t exist - 数据库(内核) -...
MySQL 启动报错 Table 'mysql.plugin' doesn't exist 启动报错： opt szy bin mysqld: Table 'mysql.plugin ' doesn 't exist141211 15:06:12 [ERROR] Can 't open t...启动报错：
/opt/szy/bin/mysqld: Table \'mysql.plugin\' doesn\'t exist
141211 15:06:12 [ERROR] Can\'t open the mysql.plug...
Mysql ibdata 丢失或损坏如何通过frm&ibd 恢复数据 - 爬虫/数据库 - 清...
...这个方法不能恢复你的数据。my.ini的设置为 innodb_file_per_table = 1。参考 http://blog.chinaunix.net/uid-24111901-id-2627876.html1、找回表结构，如果表结构没有丢失直接到下一步
a、先创建一个数据库，这个数据库必须是没有表和任何操作的...