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Rails migrations: self.up and self.down versus change
.... For example, in your case what is the reverse operation of add_column to call when you rollback? Of course it's remove_column. What is the inverse of create_table? It's drop_table. So in these cases rails know how to rollback and define a down method is superfluous (you can see in the documentatio...
Is it possible for intellij to organize imports the same way as in Eclipse?
...k,
com.*,
blank,
all other imports
FWIW, there is an Intellij plugin called "eclipse code formatter" that I evaluated for this purpose and ended up discarding, because it set up a separate shortcut (in OSX) that was already in use by core IDE functionality.
...
Gray out image with CSS?
...set that to be gray (change the alpha to get the effect).
html:
<div id="wrapper">
<img id="myImage" src="something.jpg" />
</div>
css:
#myImage {
opacity: 0.4;
filter: alpha(opacity=40); /* msie */
}
/* or */
#wrapper {
opacity: 0.4;
filter: alpha(opacit...
Getting rid of bullet points from
...
Assuming that didn't work, you might want to combine the id-based selector with the li in order to apply the css to the li elements:
#otis li {
list-style-type: none;
}
Reference:
list-style-type at the Mozilla Developer Center.
...
How can I render a list select box (dropdown) with bootstrap?
...nu which appears is boxy, less pretty, like the alert box your browser provides. Small issue really. The un-clicked selector looks exactly like a Bootstrap one, however.
– Robert
Nov 3 '16 at 8:40
...
Why declare a struct that only contains an array in C?
...'t inline: it's more efficient to pass them by const-reference, unless the callee already needs a tmp copy it can destroy. If the call / return don't optimize away, a medium to large array (thousands of bytes) is a terrible thing to pass by value.
– Peter Cordes
...
How to check if field is null or empty in MySQL?
...
You can use the IFNULL function inside the IF. This will be a little shorter, and there will be fewer repetitions of the field name.
SELECT IF(IFNULL(field1, '') = '', 'empty', field1) AS field1
FROM tablename
...
ROW_NUMBER() in MySQL
...solution is basically the same as if someone would try to find the largest id with the following query: SELECT t1.id FROM test t1 LEFT JOIN test t2 ON t1.id>t2.id WHERE t2.id IS NULL; Does not it require n*n/2 + n/2 IS NULL comparisons to find the single row? Do there happen any optimizations I d...
Join strings with a delimiter only if strings are not null or empty
...ings */) {
// Do not use:
// var args = Array.prototype.slice.call(arguments, 1);
// since it prevents optimizations in JavaScript engines (V8 for example).
// (See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/arguments)
// So we construct a ne...
Getting the parent div of element
...
This might help you.
ParentID = pDoc.offsetParent;
alert(ParentID.id);
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