大约有 12,000 项符合查询结果（耗时：0.0343秒） [XML]
WITH CHECK ADD CONSTRAINT followed by CHECK CONSTRAINT vs. ADD CONSTRAINT
...t new data, new constraints. If you disable a constraint with ALTER TABLE foo NOCHECK CONSTRAINT fk_b and then re-enable it with ALTER TABLE foo CHECK CONSTRAINT fk_b it doesn't verify the constraint. ALTER TABLE foo WITH CHECK CHECK CONSTRAINT fk_b is necessary in order to have the data verified....
How do I convert a String object into a Hash object?
..."first second > third"=>"first second > third", "after comma > foo"=>:symbolvalue, "another after comma > foo"=>10}, "bravo"=>{:symbol=>:symbolvalue, :aftercomma=>10, :anotheraftercomma=>"first second > third"}, "charlie"=>{1=>10, 2=>"first second > th...
How can I use “sizeof” in a preprocessor macro?
...macro:
/*
* Simple compile time assertion.
* Example: CT_ASSERT(sizeof foo <= 16, foo_can_not_exceed_16_bytes);
*/
#define CT_ASSERT(exp, message_identifier) \
struct compile_time_assertion { \
char message_identifier : 8 + !(exp); \
}
For example in comment MSVC tells some...
Why are empty catch blocks a bad idea? [closed]
...ed. In Python you often see this kind of construction:
try:
result = foo()
except ValueError:
result = None
So it might be OK (depending on your application) to do:
result = bar()
if result == None:
try:
result = foo()
except ValueError:
pass # Python pass is equ...
How to get the name of a function in Go?
...ion:
package main
import (
"fmt"
"reflect"
"runtime"
)
func foo() {
}
func GetFunctionName(i interface{}) string {
return runtime.FuncForPC(reflect.ValueOf(i).Pointer()).Name()
}
func main() {
// This will print "name: main.foo"
fmt.Println("name:", GetFunctionName(foo))...
What does ||= (or-equals) mean in Ruby?
.... For example:
a ||= nil # => nil
a ||= 0 # => 0
a ||= 2 # => 0
foo = false # => false
foo ||= true # => true
foo ||= false # => true
Confusingly, it looks similar to other assignment operators (such as +=), but behaves differently.
a += b translates to a = a + b
a ||= b roug...
Why can't C# interfaces contain fields?
...he runtime how to fill in all the required slots. When you say
interface IFoo { void M(); }
class Foo : IFoo { public void M() { ... } }
the class says "when you create an instance of me, stuff a reference to Foo.M in the slot for IFoo.M.
Then when you do a call:
IFoo ifoo = new Foo();
ifoo....
How to Correctly Use Lists in R?
.... Here's a simple example:
> library(hash)
> h <- hash( keys=c('foo','bar','baz'), values=1:3 )
> h[c('foo','bar')]
<hash> containing 2 key-value pairs.
bar : 2
foo : 1
In terms of usability, the hash class is very similar to a list. But the performance is better for large...
Is it possible to create a remote repo on GitHub from the CLI without opening browser?
...hub && ./script/build
Go to your repo or create empty one: mkdir foo && cd foo && git init.
Run: hub create, it'll ask you about GitHub credentials for the first time.
Usage: hub create [-p] [-d DESCRIPTION] [-h HOMEPAGE] [NAME]
Example: hub create -d Description -h examp...
How can I exclude directories from grep -R?
...busybox or GNU version older than 2.5.
Use find, for excluding directories foo and bar :
find /dir \( -name foo -prune \) -o \( -name bar -prune \) -o -name "*.sh" -print
Then combine find and the non-recursive use of grep, as a portable solution :
find /dir \( -name node_modules -prune \) -o -name...