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Ruby on Rails: How do I add a not null constraint to an existing column using a migration?
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Be careful with this approach -- if you had other attributes about that column (for example a :limit constraint), you need to repeat those attributes when using change_column, or they will be lost. For this reason, I prefer to use change_column_null
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What is the difference between Amazon S3 and Amazon EC2 instance?
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Thank you for the reply. So, if I have an EC2 instance and S3 storage, can I manage to run a server(PHP, mysql)? Or is EC2 instance enough to run a server?
– Sangam254
Jan 18 '13 at 4:56
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Stacking Divs from Bottom to Top
...e answers miss the scrollbar point of your question. And it's a tough one. If you only need this to work for modern browsers and IE 8+ you can use table positioning, vertical-align:bottom and max-height. See MDN for specific browser compatibility.
Demo (vertical-align)
.wrapper {
display: table-...
Select Row number in postgres
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You should also specify an order in OVER clause: OVER (ORDER BY id). Otherwise the order is not guaranteed.
– AlexM
Jun 14 '16 at 4:30
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Git - fatal: Unable to create '/path/my_project/.git/index.lock': File exists
...y. The error message is rather explicit as to what causes it typically, so if you have no other git processes running (which is the normal case), go ahead and delete that file.
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Start an Activity with a parameter
...y:
Bundle b = getIntent().getExtras();
int value = -1; // or other values
if(b != null)
value = b.getInt("key");
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Twitter bootstrap scrollable table
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You can only add a height percentage if the parent container has a pixel height. In your case, you'd need to do something like set .row to 500px and .span3 to 50%. If the parent doesn't have a set height the browser just defaults to the content height if you giv...
CKEditor automatically strips classes from div
...he code to how it sees fit whenever I press the source button. For example if I hit source and create a <div> ...
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Why is the .bss segment required?
...derstand is why do we have dedicated segment for uninitialized variables? If an uninitialised variable has a value assigned at run time, does the variable exist still in the .bss segment only?
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What can I use instead of the arrow operator, `->`?
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@TimSeguine If you ever want to see pretty code, then look at the documentation for inside the Macintosh. I think they invented CamelCase. Very descriptive variable names and elegantly formatted code. They managed to make their later C...