大约有 48,000 项符合查询结果（耗时：0.0745秒） [XML]
Fastest way to count exact number of rows in a very large table?
...ECT COUNT(*) FROM TABLE_NAME will be slow when the table has lots of rows and lots of columns.
25 Answers
...
What is the reason for performing a double fork when creating a daemon?
...curious as to why a double fork is necessary. I've scratched around google and found plenty of resources declaring that one is necessary, but not why.
...
What does 'synchronized' mean?
I have some questions regarding the usage and significance of the synchronized keyword.
17 Answers
...
Code coverage for Jest
...
When using Jest 21.2.1, I can see code coverage at the command line and create a coverage directory by passing --coverage to the Jest script. Below are some examples:
I tend to install Jest locally, in which case the command might look like this:
npx jest --coverage
I assume (tho...
How do I create a list of random numbers without duplicates?
I tried using random.randint(0, 100) , but some numbers were the same. Is there a method/module to create a list unique random numbers?
...
Are GUID collisions possible?
...with the same GUID. I know that microsoft uses an algorithm to generate a random GUID that has an extremely low chance of causing collisons, but is a collision still possible?
...
how to split the ng-repeat data with three columns using bootstrap
...
The most reliable and technically correct approach is to transform the data in the controller. Here's a simple chunk function and usage.
function chunk(arr, size) {
var newArr = [];
for (var i=0; i<arr.length; i+=size) {
newArr.pus...
Maximum number of records in a MySQL database table
...utoincrement field. What would happen if I add milions of records? How to handle this kind of situations?
Thx!
8 Answers
...
Update relationships when saving changes of EF4 POCO objects
Entity Framework 4, POCO objects and ASP.Net MVC2. I have a many to many relationship, lets say between BlogPost and Tag entities. This means that in my T4 generated POCO BlogPost class I have:
...
Items in JSON object are out of order using “json.dumps”?
...
Both Python dict (before Python 3.7) and JSON object are unordered collections. You could pass sort_keys parameter, to sort the keys:
>>> import json
>>> json.dumps({'a': 1, 'b': 2})
'{"b": 2, "a": 1}'
>>> json.dumps({'a': 1, 'b': 2},...