大约有 48,000 项符合查询结果（耗时：0.0784秒） [XML]
Is it a good idea to index datetime field in mysql?
...n/5.0/en/mysql-indexes.html
This makes your datetime column an excellent candidate for an index if you are going to be using it in conditions frequently in queries. If your only condition is BETWEEN NOW() AND DATE_ADD(NOW(), INTERVAL 30 DAY) and you have no other index in the condition, MySQL will...
Using boolean values in C
...e 1
#define false 0
Explanation
Option 1 will work only if you use C99 and it's the "standard way" to do it. Choose this if possible.
Options 2, 3 and 4 will have in practice the same identical behavior. #2 and #3 don't use #defines though, which in my opinion is better.
If you are undecided, ...
How should I log while using multiprocessing in Python?
...locks so that you don't garble things up in sys.stderr (or whatever filehandle) by having multiple processes writing to it simultaneously.
...
Solutions for INSERT OR UPDATE on SQL Server
...ford & @Esteban show general idea but error-prone.
To avoid deadlocks and PK violations you can use something like this:
begin tran
if exists (select * from table with (updlock,serializable) where key = @key)
begin
update table set ...
where key = @key
end
else
begin
insert into tab...
Is there a better alternative than this to 'switch on type'?
...-types
Short version: TypeSwitch is designed to prevent redundant casting and give a syntax that is similar to a normal switch/case statement. For example, here is TypeSwitch in action on a standard Windows form event
TypeSwitch.Do(
sender,
TypeSwitch.Case<Button>(() => textBox1.T...
How does the paste image from clipboard functionality work in Gmail and Google Chrome 12+?
...on of Chrome. I tried this with my version of Chrome (12.0.742.91 beta-m) and it works great using control keys or the context menu.
...
What's the difference between xsd:include and xsd:import?
What's the difference between xsd:include and xsd:import ? When would you use one instead of the other, and when might it not matter?
...
How to get the contents of a webpage in a shell variable?
In Linux how can I fetch an URL and get its contents in a variable in shell script?
6 Answers
...
Apache Spark: map vs mapPartitions?
What's the difference between an RDD's map and mapPartitions method? And does flatMap behave like map or like mapPartitions ? Thanks.
...
Post-install script with Python setuptools
...ile as part of the setuptools setup.py file so that a user can run the command:
7 Answers
...