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In Postgresql, force unique on combination of two columns
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CREATE TABLE someTable (
id serial primary key,
col1 int NOT NULL,
col2 int NOT NULL,
unique (col1, col2)
)
autoincrement is not postgresql. You want a serial.
If col1 and col2 make a unique and can't be null then they make a good prim...
Get PHP class property by string
How do I get a property in a PHP based on a string? I'll call it magic . So what is magic ?
12 Answers
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JavaScript: how to change form action attribute value based on selection?
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Simple and easy in javascipt
<script>
document.getElementById("selectsearch").addEventListener("change", function(){
var get_form = document.getElementById("search-form") // get form
get_form.action = '/search/' + this.value; // assign value
});
</script>
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Random record from MongoDB
...t would have the fatal flaw of not matching anything if the $sample stage didn't select any matching documents.
– JohnnyHK
Apr 19 at 0:21
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JavaScript: Get image dimensions
...here outside the viewport) - then the dimensions are available right after calling document.appendChild().
– JustAndrei
Apr 7 '15 at 10:51
1
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google chrome extension :: console.log() from background page?
If I call console.log('something'); from the popup page, or any script included off that it works fine.
11 Answers
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Recommended way of making React component/div draggable
...s case, the draggable would still own the "am I dragging" state, but would call this.props.onChange(x, y) whenever a mousemove event occurs.
Scenario 2
the parent only needs to own the "non-moving position", and so the draggable would own it's "dragging position" but onmouseup it would call this....
Null or default comparison of generic argument in C#
...1 that happens to implement IEquatable<T1> needs to be treated identically to a T2 that does not - so no, it will not spot a Equals(T1 other) method, even if it exists at runtime. In both cases, there is also null to think about (either object). So with generics, I would use the code I posted...
Access denied for user 'root'@'localhost' while attempting to grant privileges. How do I grant privi
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Notice how the output of
SHOW GRANTS FOR 'root'@'localhost';
did not say 'ALL PRIVILEGES' but had to spell out what root@localhost has.
GRANT ALL PRIVILEGES will fail, because a user can not grant what he/she does not have,
and the server seem to think something is not here ...
Now, w...
Semaphore vs. Monitors - what's the difference?
...cuting a member function of the object then any other thread that tries to call a member function of that object will have to wait until the first has finished.
A Semaphore is a lower-level object. You might well use a semaphore to implement a monitor. A semaphore essentially is just a counter. Whe...