大约有 31,840 项符合查询结果（耗时：0.0536秒） [XML]
“INSERT IGNORE” vs “INSERT … ON DUPLICATE KEY UPDATE”
...NULL into a column with a NOT NULL constraint.
Inserting a row to a partitioned table, but the values you insert don't map to a partition.
If you use REPLACE, MySQL actually does a DELETE followed by an INSERT internally, which has some unexpected side effects:
A new auto-increment ID is alloc...
Remove duplicates in the list using linq
...ass> and List<string>. My custom class has various items in which one is DCN number and list<string> has only DCN number. So I need to check the List<Custom_Class> contains any dcn from List<string>. For example suppose List1 = List<Custom_Class> and List2 = List<...
How can I get LINQ to return the object which has the max value for a given property? [duplicate]
... .FirstOrDefault() is probably a better choice, since it's a little less prone to issues.
– Dortimer
May 1 '19 at 16:55
2
...
Which equals operator (== vs ===) should be used in JavaScript comparisons?
...cally to the abstract equality operator (==) except no type conversion is done, and the types must be the same to be considered equal.
Reference: Javascript Tutorial: Comparison Operators
The == operator will compare for equality after doing any necessary type conversions. The === operator will n...
How to convert comma-separated String to List?
... the backslash in strings, so you get \\s*
– andrewrjones
Nov 14 '12 at 9:44
9
...
Why can't I save CSS changes in Firebug? [closed]
...it works great highlighting the changed lines. Just click Save and you're done! :)
Here's a video explaining this and much more: Google I/O 2011: Chrome Dev Tools Reloaded
I hope it helps if it doesn't matter to you changing browser while editing your CSS files. I made the change already for now, ...
Create a string of variable length, filled with a repeated character
So, my question has been asked by someone else in it's Java form here: Java - Create a new String instance with specified length and filled with specific character. Best solution?
...
Unstaged changes left after git reset --hard
...
This works, but I do not exactly understand why. Anyone care to explain each command?
– Edwin Stoteler
Mar 20 '15 at 14:04
19
...
How do I install pip on macOS or OS X?
...
⚡️ TL;DR — One line solution.
All you have to do is:
sudo easy_install pip
2019: ⚠️easy_install has been deprecated. Check Method #2 below for preferred installation!
I made a gif, coz. why not?
Details:
⚡️ OK, ...
Django: Why do some model fields clash with each other?
...
For someone just learning the framework, this would not be obvious.
– jkyle
Feb 23 '11 at 4:48
3
...