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Add unique constraint to combination of two columns
...UAL
ON USER_UND(UUL_USR_IDF, UUL_ATUAL)
WHERE UUL_ATUAL = 1;
Here are my test cases:
SELECT * FROM USER_UND WHERE UUL_USR_IDF = 137
insert into USER_UND values (137, 22, 1) --I CAN NOT => Cannot insert duplicate key row in object 'dbo.USER_UND' with unique index 'UQ_USR_UND_UUL_USR_IDF_UUL_AT...
Default value of function parameter
...
int Add(int a, int b);
lib.cpp
int Add(int a, int b = 3) {
...
}
test.cpp
#include "lib.h"
int main() {
Add(4);
}
The compilation of test.cpp will not see the default parameter declaration, and will fail with an error.
For this reason, the default parameter definition is usually s...
What is the default location for MSBuild logs?
... and press CTRL + S to save. Visual Studio will prompt you for a location (tested with Visual Studio 2017, but I'm assuming this works in earlier versions too).
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What is the Swift equivalent of isEqualToString in Objective-C?
... But, unless I'm missing something, it doesn't seem you can test the identity between Strings: 'String' does not conform to protocol 'AnyObject'.
– user1040049
May 25 '15 at 16:45
...
What is the exact meaning of IFS=$'\n'?
...
ANSI C-quoted strings is a key point. Thanks to @mklement0 .
You can test ANSI C-quoted strings with command od.
echo -n $'\n' | od -c
echo -n '\n' | od -c
echo -n $"\n" | od -c
echo -n "\n" | od -c
Outputs:
0000000 \n
0000001
0000000 \ n
0000002
0000000 \ n
0000002
000...
CSS Selector “(A or B) and C”?
...
@MaxMurphy Have you tested this?
– Šime Vidas
Aug 24 '14 at 12:28
4
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Android Preferences: How to load the default values when the user hasn't used the preferences-screen
...rsing if your application has more than one entry point. Unfortunately the test is not made per preference file, so if you have more than one preference file you must code true on all but the first.
If you are worried about efficiency, you could code something like this.
final static private int S...
File Hash 扩展：文件哈希计算和 Base64 编码文件，sha256、sha512 哈希 ·...
...
when Button1.Click() {
Label1.Text = GetFileSha2561.GetSha256("/sdcard/test.txt")
Label2.Text = JustBase641.Base64TextEncode(TextBox1.Text)
}
同时计算 SHA256 和 SHA512
when Button1.Click() {
Label1.Text = GetFileSha2561.GetSha256("/sdcard/test.txt")
Label2.Te...
Possibility of duplicate Mongo ObjectId's being generated in two different collections?
... design that relied on _id uniqueness across collections.
One can easily test this in the mongo shell:
MongoDB shell version: 1.6.5
connecting to: test
> db.foo.insert({_id: 'abc'})
> db.bar.insert({_id: 'abc'})
> db.foo.find({_id: 'abc'})
{ "_id" : "abc" }
> db.bar.find({_id: 'abc'})...
base64 encoded images in email signatures
... may be the more widely supported solution, but the only way to know is to test several major email clients with different security settings applied. Further complicating the matter is that you can receive email both on the web and in a variety of clients. For example, Gmail may behave differently w...