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Update just one gem with bundler
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note: this command will update one gem without dependencies of it
– mmike
Jun 4 '18 at 11:07
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Bogus foreign key constraint fail
...eference
The innodb internal data dictionary is out of sync with the mysql one.
You can see which table it was (one of them, anyway) by doing a "SHOW ENGINE INNODB STATUS" after the drop fails.
If it turns out to be the latter case, I'd dump and restore the whole server if you can.
MySQL 5.1 and...
Convert a list to a data frame
...x means that all data will be coerced into a common type. I.e. if you have one column of character data and one column of numeric data the numeric data will be coerced to string by matrix() and then both to factor by data.frame().
– Ian Sudbery
Mar 15 '13 at 10...
What is the difference between typeof and instanceof and when should one be used vs. the other?
.../object
{} instanceof Object; // true
typeof {}; // object
And the last one is a little bit tricky:
typeof null; // object
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In Python how should I test if a variable is None, True or False
I have a function that can return one of three things:
6 Answers
6
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What is the difference between integration and unit tests?
...en, since they stress the code in a scenario close to reality. They invoke one or more software methods or features and test if they act as expected.
On the opposite, a Unit test testing a single method relies on the (often wrong) assumption that the rest of the software is correctly working, becau...
Understanding the meaning of the term and the concept - RAII (Resource Acquisition is Initialization
...lling you what to do: Acquire your resource in a constructor! I would add: one resource, one constructor. UTSTTC is just one application of that, RAII is much more.
Resource Management sucks. Here, resource is anything that needs cleanup after use. Studies of projects across many platforms show the...
How do I use cascade delete with SQL Server?
I have 2 tables: T1 and T2, they are existing tables with data. We have a one to many relationship between T1 and T2. How do I alter the table definitions to perform cascading delete in SQL Server when a record from T1 is deleted, all associated records in T2 also deleted.
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What is “String args[]”? parameter in main method Java
...String objects.
In other words, if you run your program as java MyProgram one two then args will contain ["one", "two"].
If you wanted to output the contents of args, you can just loop through them like this...
public class ArgumentExample {
public static void main(String[] args) {
fo...
How to check if a map contains a key in Go?
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One line answer:
if val, ok := dict["foo"]; ok {
//do something here
}
Explanation:
if statements in Go can include both a condition and an initialization statement. The example above uses both:
initializes two vari...