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Working with huge files in VIM
...s a 300GB mysql dump and I wanted to get rid of the DROP and change CREATE TABLE to CREATE TABLE IF NOT EXISTS so didn't want to run two invocations of sed. I wrote this quick Ruby script to dupe the file with those changes:
#!/usr/bin/env ruby
matchers={
%q/^CREATE TABLE `foo`/ => %q/CREA...
SQL Server Index Naming Conventions [closed]
...dexes
All of my index name take the form of
<index or key type>_<table name>_<column 1>_<column 2>_<column n>
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不同品牌的防火墙组成高可靠性集群 - 更多技术 - 清泛网 - 专注C/C++及内核技术
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知识准备
一、原理说明
1、路由表（table）从0到255进行编号，每个编号可以对应一个别名，编号和别名的对应关系在linux下放在/etc/iproute2/rt_tables这个文件里，一般0编号
的table对应的别名为upspec，255编号对应...
What columns generally make good indexes?
...portant role in query optimization and searching the results speedily from tables. So it is most important step to select which columns to be indexed. There are two major places where we can consider indexing: columns referenced in the WHERE clause and columns used in JOIN clauses. In short, such co...
What is the difference between Scope_Identity(), Identity(), @@Identity, and Ident_Current()?
....
The ident_current(name) returns the last identity created for a specific table or view in any session.
The identity() function is not used to get an identity, it's used to create an identity in a select...into query.
The session is the database connection. The scope is the current query or the c...
What is a NullReferenceException, and how do I fix it?
...that C# has the concept of nullable datatypes for variables (like database tables can have nullable fields) - you can assign null to them to indicate there is no value stored in it, for example int? a = null; where the question mark indicates it is allowed to store null in variable a. You can check ...
Select values from XML field in SQL Server 2008
...alue('(/person//lastName/node())[1]', 'nvarchar(max)') as LastName
FROM [myTable]
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Is there a version control system for database structure changes?
...the version (such as removing a column). Each migration is numbered, and a table keeps track of your current db version.
To migrate up, you run a command called "db:migrate" which looks at your version and applies the needed scripts. You can migrate down in a similar way.
The migration scripts the...
Why is SSE scalar sqrt(x) slower than rsqrt(x) * x?
... there are some info, especially about rsqrt (cpu is using internal lookup table with huge approximation, which makes it much simpler to get the result). It may seem, that rsqrt is so much faster than sqrt, that 1 additional mul operation (which isn't to costly) might not change the situation here. ...
Div width 100% minus fixed amount of pixels
How can I achieve the following structure without using tables or JavaScript? The white borders represent edges of divs and aren't relevant to the question.
...