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Is it a good idea to index datetime field in mysql?
...it in conditions frequently in queries. If your only condition is BETWEEN NOW() AND DATE_ADD(NOW(), INTERVAL 30 DAY) and you have no other index in the condition, MySQL will have to do a full table scan on every query. I'm not sure how many rows are generated in 30 days, but as long as it's less t...
Ant: How to execute a command for each file in directory?
... or type foreach". If I understand correctly, this means, foreach is an unknown keyword.
– ivan_ivanovich_ivanoff
Sep 23 '09 at 19:48
4
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Why prefer two's complement over sign-and-magnitude for signed numbers?
... to 4 bits for size). In the two's complement way, they are 0010 and 1111. Now, let's say I want to add them.
Two's complement addition is very simple. You add numbers normally and any carry bit at the end is discarded. So they're added as follows:
0010
+ 1111
=10001
= 0001 (discard the carry)
...
How to check status of PostgreSQL server Mac OS X
...o get them to take effect, remember to source it like so:
$ . ~/.bashrc
Now, try it and you should get something like this:
$ show-pg-status
pg_ctl: server is running (PID: 11030)
/usr/local/Cellar/postgresql/9.2.4/bin/postgres
...
how to check and set max_allowed_packet mysql variable [duplicate]
...
@YusufIbrahim Short answer: I don't know. But a quick scan of this article suggests that it should be possible.
– morphatic
Nov 29 '19 at 18:54
...
One Activity and all other Fragments [closed]
...icly available android-support-v4-googlemaps.
Ultimately most the devs I know that went the one Activity route have gone back to multiple Activities to simplify their code. UI wise, on a tablet, you are some times stuck using a single Activity just to achieve what ever crazy interaction your desig...
Node.js spawn child process and get terminal output live
...s for a second, outputs 'hi', sleeps for 1 second, and so on and so forth. Now I thought I would be able to tackle this problem with this model.
...
How to read a (static) file from inside a Python package?
...t cannot be a directory).
For the example asked in the question, we must now:
make the <your_package>/templates/ into a proper package, by creating an empty __init__.py file in it,
so now we can use a simple (possibly relative) import statement (no more parsing package/module names),
and s...
Boost智能指针——shared_ptr - C/C++ - 清泛网 - 专注C/C++及内核技术
...ptr<implementation> sp1(new implementation());
std::cout<<"The Sample now has "<<sp1.use_count()<<" references\n";
boost::shared_ptr<implementation> sp2 = sp1;
std::cout<<"The Sample now has "<<sp2.use_count()<<" references\n";
sp1.reset();
std::cout<<"After Reset sp...
App Inventor Tutorials and Examples: Dynamic Table Layout | Pura Vida Apps
...in the App Inventor Forum, how to display a table in App Inventor without knowing how many rows will be supplied. And let me add to this requirement, without knowing how many columns will be supplied! Thank you Craig! Your JavaScript example helped me to set up this solution. ...