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What is an invariant?
The word seems to get used in a number of contexts. The best I can figure is that they mean a variable that can't change. Isn't that what constants/finals (darn you Java!) are for?
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How can I expand and collapse a using javascript?
I have created a list on my site. This list is created by a foreach loop that builds with information from my database. Each item is a container with different sections, so this is not a list like 1, 2, 3... etc. I am listing repeating sections with information. In each section, there is a subse...
How to use a link to call JavaScript?
How to use a link to call JavaScript code?
9 Answers
9
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Difference between a theta join, equijoin and natural join
I'm having trouble understanding relational algebra when it comes to theta joins, equijoins and natural joins. Could someone please help me better understand it? If I use the = sign on a theta join is it exactly the same as just using a natural join?
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SQLite Concurrent Access
Does SQLite3 safely handle concurrent access by multiple processes
reading/writing from the same DB? Are there any platform exceptions to that?
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Using emit vs calling a signal as if it's a regular function in Qt
Let's say I have this signal:
3 Answers
3
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What is the optimal length for user password salt? [closed]
Any salt at all will obviously help when salting and hashing a user's password. Are there any best practices for how long the salt should be? I'll be storing the salt in my user table, so I would like the best tradeoff between storage size and security. Is a random 10 character salt enough? Or ...
Why use Ruby instead of Smalltalk? [closed]
Ruby is becoming popular , largely from the influence Ruby on Rails, but it feels like it is currently struggling through its adolescence. There are a lot of similarities between Ruby and Smalltalk -- maglev is a testament to that. Despite having a more unusual syntax, Smalltalk has all (if not m...
Adding a UILabel to a UIToolbar
I'm trying to add a label to my toolbar. Button works great, however when I add the label object, it crashes. Any ideas?
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Delete all lines beginning with a # from a file
All of the lines with comments in a file begin with # . How can I delete all of the lines (and only those lines) which begin with # ? Other lines containing # , but not at the beginning of the line should be ignored.
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