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How can I use UUIDs in SQLAlchemy?
... is an example:
from sqlalchemy.dialects.postgresql import UUID
from flask_sqlalchemy import SQLAlchemy
import uuid
db = SQLAlchemy()
class Foo(db.Model):
# id = db.Column(db.Integer, primary_key=True)
id = db.Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4, unique=True, n...
Select the values of one property on all objects of an array in PowerShell
...
$objects | % Name # short for: $objects | ForEach-Object -Process { $_.Name }
For the sake of completeness: The little-known PSv4+ .ForEach() array method, more comprehensivel discussed in this article, is yet another alternative:
# By property name (string):
$objects.ForEach('Name')
# By s...
BLE协议—广播和扫描 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...广播方式的报文有4种，分别为可连接的非定向广播（ADV_IND）、可连接的定向广播（ADV_DIRECT_IND）、可扫描非定向广播（ADV_SCAN_IND）、不可连接的非定向广播（ADV_NONCONN_IND）
4种广播的使用场景各不相同
可连接的非定向广播（A...
C++ display stack trace on exception
...
On the home page of StackTrace, I see throw stack_runtime_error. Am I correct in deducing that this lib only works for exceptions derived from that class, and not for std::exception or exceptions from third-party libraries?
– Thomas
No...
Function return value in PowerShell
... a single line.
You can read more about the return semantics on the about_Return page on TechNet, or by invoking the help return command from PowerShell itself.
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Auto layout constraints issue on iOS7 in UITableViewCell
...n the cell is reused like this:
For Static UITableViewController:
#ifdef __IPHONE_OS_VERSION_MIN_REQUIRED
#if __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_8_0
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [sup...
Why does SSL handshake give 'Could not generate DH keypair' exception?
...s JCE provider suggestion did.
Here are the steps I took using Java 1.6.0_65-b14-462 on Mac OSC 10.7.5
1) Download these jars:
bcprov-jdk15on-154.jar
bcprov-ext-jdk15on-154.jar
2) move these jars to $JAVA_HOME/lib/ext
3) edit $JAVA_HOME/lib/security/java.security as follows:
security.provid...
How to read keyboard-input?
...
try
raw_input('Enter your input:') # If you use Python 2
input('Enter your input:') # If you use Python 3
and if you want to have a numeric value
just convert it:
try:
mode=int(raw_input('Input:'))
except ValueError:
...
Why are preprocessor macros evil and what are the alternatives?
....
Another example is "if else" in macros, say we have this:
#define safe_divide(res, x, y) if (y != 0) res = x/y;
and then
if (something) safe_divide(b, a, x);
else printf("Something is not set...");
It actually becomes completely the wrong thing....
Replacement: real functions.
3) Ma...
Reload django object from database
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As of Django 1.8 refreshing objects is built in. Link to docs.
def test_update_result(self):
obj = MyModel.objects.create(val=1)
MyModel.objects.filter(pk=obj.pk).update(val=F('val') + 1)
# At this point obj.val is still 1, but the value in the database
# was updated to 2. The ob...