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How can I define a composite primary key in SQL?
...(from that table). If a primary key consists of two or more columns it is called a composite primary key. It is defined as follows:
CREATE TABLE voting (
QuestionID NUMERIC,
MemberID NUMERIC,
PRIMARY KEY (QuestionID, MemberID)
);
The pair (QuestionID,MemberID) must then be unique for the ta...
How to check iOS version?
...system version as an indication of device or OS capabilities. There is usually a more reliable method of checking whether a particular feature or class is available.
Checking for the presence of APIs:
For example, you can check if UIPopoverController is available on the current device using NSCla...
Groovy: what's the purpose of “def” in “def x = 0”?
...e bindings for the current script and groovy treats it (mostly) like a globally scoped variable:
x = 1
assert x == 1
assert this.binding.getVariable("x") == 1
Using the def keyword instead does not put the variable in the scripts bindings:
def y = 2
assert y == 2
try {
this.binding.getVari...
What is the Invariant Culture?
... be read and written regardless of the culture the user has defined.
Basically it is a specific culture that is artificial and will not change.
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Python Git Module experiences? [closed]
.../kennethreitz/legit/blob/develop/legit/scm.py
– forivall
Sep 17 '12 at 17:17
9
Based on this answ...
Ternary operator is twice as slow as an if-else block?
...several additional registers available, and each register is 64-bits. This allows the X64 JIT to perform the inner loop entirely using registers aside from loading i from the array, while the X86 JIT places several stack operations (memory access) in the loop.
value is a 64-bit integer, which requir...
How can you do anything useful without mutable state?
...me, there are
tons of state variables, beginning
with the positions of all the
characters, who tend to move around
constantly. How can you possibly do
anything useful without keeping track
of changing values?
If you're interested, here's a series of articles which describe game program...
How I can I lazily read multiple JSON values from a file/stream in Python?
...
JSON generally isn't very good for this sort of incremental use; there's no standard way to serialise multiple objects so that they can easily be loaded one at a time, without parsing the whole lot.
The object per line solution that y...
Convert.ChangeType() fails on Nullable Types
...e?
– coloradocolby
May 13 '19 at 20:01
@threadster You can't use default operator ona variable of type 'Type'. See st...
github: No supported authentication methods available
...d with SSH.
if you ever used Telnet, it's like that (but more secure): it allows you to remotely access the bash shell (command line) of a Linux host.
PuTTY
PuTTY is a free and open-source terminal emulator, serial console and
network file transfer application. It supports several network
protocol...