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Which MySQL data type to use for storing boolean values
...iate because it uses zero data bytes:
some_flag CHAR(0) DEFAULT NULL
To set it to true, set some_flag = '' and to set it to false, set some_flag = NULL.
Then to test for true, check if some_flag IS NOT NULL, and to test for false, check if some_flag IS NULL.
(This method is described in "High P...
Delete sql rows where IDs do not have a match from another table
...
@Pacerier - NOT IN (NULL) returns an empty result set so NULLs need to be excluded. But an id column probably won't be nullable anyway hence "unlikely to be needed"
– Martin Smith
Apr 10 '15 at 16:40
...
Make: how to continue after a command fails?
...ally ignore errors on a single line, you can simply suffix it with ; true, setting the return value to 0. For example:
rm .lambda .lambda_t .activity .activity_t_lambda 2>/dev/null; true
This will redirect stderr output to null, and follow the command with true (which always returns 0, causin...
How to use unicode characters in Windows command line?
...I already said: To input/output Unicode in a console, one does not need to set the codepage.
The details
To read/write Unicode to a console, an application (or its C runtime library) should be smart enough to use not File-I/O API, but Console-I/O API. (For an example, see how Python does it.)
L...
read subprocess stdout line by line
...bprocess to call a linux utility that is very noisy. I want to store all of the output to a log file and show some of it to the user. I thought the following would work, but the output doesn't show up in my application until the utility has produced a significant amount of output.
...
SQL Server: Make all UPPER case to Proper Case/Title Case
...erCase(@Text as varchar(8000))
returns varchar(8000)
as
begin
declare @Reset bit;
declare @Ret varchar(8000);
declare @i int;
declare @c char(1);
if @Text is null
return null;
select @Reset = 1, @i = 1, @Ret = '';
while (@i <= len(@Text))
select @c = substring(@Text, @i, ...
Pandas index column title or name
...
You can just get/set the index via its name property
In [7]: df.index.name
Out[7]: 'Index Title'
In [8]: df.index.name = 'foo'
In [9]: df.index.name
Out[9]: 'foo'
In [10]: df
Out[10]:
Column 1
foo
Apples 1...
How to wait for several Futures?
...*) extends Actor {
var origSender: ActorRef = null
var futsRemaining: Set[Future[_]] = futs.toSet
override def receive = {
case () =>
origSender = sender
for(f <- futs)
f.onComplete(result => self ! if(result.isSuccess) f else false)
case false =>
...
Android - Pulling SQlite database android device
... dst.close();
}
}
} catch (Exception e) {
}
Don't forget to set the permission to write on SD in your manifest, like below.
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
...
MySQL/Amazon RDS error: “you do not have SUPER privileges…”
... http://getasysadmin.com/2011/06/amazon-rds-super-privileges/, you need to set log_bin_trust_function_creators to 1 in AWS console, to load your dump file without errors.
If you want to ignore these errors, and load the rest of the dump file, you can use the -f option:
mysql -f my_database -u my_u...