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Check if my app has a new version on AppStore
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91
Here is a simple code snippet that lets you know if the current version is different
-(BOOL) ne...
Does MySQL ignore null values on unique constraints?
...ws multiple NULLs in a column with a unique constraint.
CREATE TABLE table1 (x INT NULL UNIQUE);
INSERT table1 VALUES (1);
INSERT table1 VALUES (1); -- Duplicate entry '1' for key 'x'
INSERT table1 VALUES (NULL);
INSERT table1 VALUES (NULL);
SELECT * FROM table1;
Result:
x
NULL
NULL
1
This i...
How do I return multiple values from a function? [closed]
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select and update database record with a single queryset
...et object update method:
MyModel.objects.filter(pk=some_value).update(field1='some value')
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Unicode equivalents for \w and \b in Java regular expressions?
...ious other properties, too. It now tracks The Unicode Standard, in both RL1.2 and RL1.2a from UTS#18: Unicode Regular Expressions. This is an exciting and dramatic improvement, and the development team is to be commended for this important effort.
Java’s Regex Unicode Problems
The problem wit...
Why is i++ not atomic?
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125
i++ is probably not atomic in Java because atomicity is a special requirement which is not pre...
Measure execution time for a Java method [duplicate]
...em.out.println(stopTime - startTime);
In Java 8 (output format is ISO-8601):
Instant start = Instant.now();
Thread.sleep(63553);
Instant end = Instant.now();
System.out.println(Duration.between(start, end)); // prints PT1M3.553S
Guava Stopwatch:
Stopwatch stopwatch = Stopwatch.createStarted()...
Linux bpftrace学习笔记（持续更新） - 操作系统(内核) - 清泛网移动版 - ...
...BPF性能工具及其可见性bpftrace安装请参考：bpftrace-install。1、查看程序在打开哪些文件： bpftrace -e & 39;tracepoint:syscalls:sys_enter_open { printf("%s %s n
图：BPF性能工具及其可见性
bpftrace安装请参考：bpftrace-install 。
1、查看哪些程...
Multiple simultaneous downloads using Wget?
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