大约有 40,000 项符合查询结果（耗时：0.0669秒） [XML]
E11000 duplicate key error index in mongodb mongoose
... null value.
In other words, a sparse index is ok with multiple documents all having null values.
sparse indexes
From comments:
Your error says that the key is named mydb.users.$email_1 which makes me suspect that you have an index on both users.email and users.local.email (The former being old an...
Tool to Unminify / Decompress JavaScript [closed]
...iderMonkey and Rhino you can wrap any code into an anonymous function and call its toSource method, which will give you a nicely formatted source of the function.
toSource also strips comments.
E. g.:
(function () { /* Say hello. */ var x = 'Hello!'; print(x); }).toSource()
Will be converted to...
Cannot read configuration file due to insufficient permissions
... is same as above, but a little longer and simpler and improved.
First of all: you don't have to change anything in your config file. It's OK. The problem is with windows file permissions.
This problems occurs because your application can not access and read web.config file.
Make the file accessi...
What is “thread local storage” in Python, and why do I need it?
In Python specifically, how do variables get shared between threads?
5 Answers
5
...
Shortcut to create properties in Visual Studio?
I have seen some people creating properties in C# really fast, but how did they do it?
16 Answers
...
When should I use perror(“…”) and fprintf(stderr, “…”)?
...should use fprintf(stderr, fmt, ...). For example, strtol will return LONG_MAX or LONG_MIN if a string is out of range and set errno to ERANGE. So if strtol fails due to out of range, I would use perror.
– freeboy1015
Aug 24 '12 at 2:22
...
Confused about Service vs Factory
...
All angular services are singletons:
Docs (see Services as singletons): https://docs.angularjs.org/guide/services
Lastly, it is important to realize that all Angular services are application singletons. This means that t...
Why do we need C Unions?
...le types together:
enum Type { INTS, FLOATS, DOUBLE };
struct S
{
Type s_type;
union
{
int s_ints[2];
float s_floats[2];
double s_double;
};
};
void do_something(struct S *s)
{
switch(s->s_type)
{
case INTS: // do something with s->s_ints
break;
case F...
How to trace the path in a Breadth-First Search?
... found
if node == end:
return path
# enumerate all adjacent nodes, construct a new path and push it into the queue
for adjacent in graph.get(node, []):
new_path = list(path)
new_path.append(adjacent)
queue.append(new_path)
prin...
How to format an inline code in Confluence?
...ed" option applies to the entire line. The only way to do it (without installing the wikitext editing plugin) is to pick monospaced font.
– HDave
Mar 27 '13 at 17:14
16
...