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Can I add a UNIQUE constraint to a PostgreSQL table, after it's already created?
I have the following table:
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Is key-value observation (KVO) available in Swift?
...e any key differences that weren't otherwise present when using key-value observation in Objective-C?
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What does 'synchronized' mean?
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The synchronized keyword is all about different threads reading and writing to the same variables, objects and resources. This is not a trivial topic in Java, but here is a quote from Sun:
synchronized methods enable a simple
strategy for preventing t...
SQL Server - transactions roll back on error?
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You can put set xact_abort on before your transaction to make sure sql rolls back automatically in case of error.
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List tables in a PostgreSQL schema
When I do a \dt in psql I only get a listing of tables in the current schema ( public by default).
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HTML input - name vs. id [duplicate]
When using the HTML <input> tag, what is the difference between the use of the name and id attributes especially that I found that they are sometimes named the same?
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AngularJS $resource RESTful example
I would like to use $resource to call my RESTful web service, (which I am still working on) but I would like to find out if I got my AngularJS script correct first.
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SVG gradient using CSS
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Just use in the CSS whatever you would use in a fill attribute.
Of course, this requires that you have defined the linear gradient somewhere in your SVG.
Here is a complete example:
rect {
cursor: pointer;
shape-rendering: crispEdges;
fill: url(#MyGradient);
}
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Non-static variable cannot be referenced from a static context
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You must understand the difference between a class and an instance of that class. If you see a car on the street, you know immediately that it's a car even if you can't see which model or type. This is because you compare what you see with the class "car". The...
MySQL: Large VARCHAR vs. TEXT?
I've got a messages table in MySQL which records messages between users. Apart from the typical ids and message types (all integer types) I need to save the actual message text as either VARCHAR or TEXT. I'm setting a front-end limit of 3000 characters which means the messages would never be inserte...