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Why can't I use the 'await' operator within the body of a lock statement?
The await keyword in C# (.NET Async CTP) is not allowed from within a lock statement.
8 Answers
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Check if a user has scrolled to the bottom
...ight of the visible window and checks if that equals the height of the overall content (document). If you wanted to instead check if the user is near the bottom, it'd look something like this:
$(window).scroll(function() {
if($(window).scrollTop() + $(window).height() > $(document).height() ...
Dashed line border around UIView
...t@2x.png and test@3x.png with size of 240x240 and 360x360 which is used in all the apple device automatically with it's related name. (i.e. test.png is use in iPhone 4, test@2x will useful for iPhone 4s, 5, 5s, 6, 6s and twst@3x will useful for iPhone 6 plus, 6s plus.
– Paras J...
What is the difference between char, nchar, varchar, and nvarchar in SQL Server?
...torage space for number of characters you specify even if you don't use up all that space.
varchar and nvarchar are variable-length which will only use up spaces for the characters you store. It will not reserve storage like char or nchar.
nchar and nvarchar will take up twice as much storage spac...
Want to find records with no associated records in Rails
... the DISTINCT. Otherwise, I think you'd want to normalize out the data and index in that case. I might do that by creating a friend_ids hstore or serialized column. Then you could say Person.where(friend_ids: nil)
– Unixmonkey
Dec 20 '16 at 16:02
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How to have a default option in Angular.js select box
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My problem is that the index of the option is returned from a "submit" on the form. What I need is what you are calling option.name, which is what was returned from a plain old rails form. The checkbox and radio buttons work fine since you use ng-r...
How can I multiply and divide using only bit shifting and adding?
...kes a constant multiple of time compared to addition and shifting. If I recall correctly, modern processors, if pipelined properly, can do multiplication just about as fast as addition, by messing with the utilization of the ALUs (arithmetic units) in the processor.
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Cannot delete or update a parent row: a foreign key constraint fails
... (`advertiser_id`)
REFERENCES `jobs` (`advertiser_id`);
...is actually the opposite to what it should be. As it is, it means that you'd have to have a record in the jobs table before the advertisers. So you need to use:
ALTER TABLE `jobs`
ADD CONSTRAINT `advertisers_ibfk_1` FOREIGN KEY...
Use '=' or LIKE to compare strings in SQL?
...s used for equality test (as defined by the COLLATION in use).
= can use indexes while LIKE queries usually require testing every single record in the result set to filter it out (unless you are using full text search) so = has better performance.
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Cannot issue data manipulation statements with executeQuery()
...) returns a ResultSet. I'm not as familiar with Java/MySQL, but to create indexes you probably want a executeUpdate().
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