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Computed / calculated / virtual / derived columns in PostgreSQL
... Postgres 11 generated columns are not supported - as defined in the SQL standard and implemented by some RDBMS including DB2, MySQL and Oracle. Nor the similar "computed columns" of SQL Server.
STORED generated columns are introduced with Postgres 12. Trivial example:
CREATE TABLE tbl (
int1 ...
Dynamic type languages versus static type languages
What are the advantages and limitations of dynamic type languages compared to static type languages?
9 Answers
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Attempt to present UIViewController on UIViewController whose view is not in the window hierarchy
Just started using Xcode 4.5 and I got this error in the console:
33 Answers
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Soft keyboard open and close listener in an activity in Android
... set some other View 's visibility to Gone when the soft keyboard opens and also when the user clicks on the first EditText and also when the soft keyboard closes from the same EditText on the back button press. Then I want to set some other View 's visibility to visible.
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What are the differences between Abstract Factory and Factory design patterns?
... Difference Between The Two
The main difference between a "factory method" and an "abstract factory" is that the factory method is a method, and an abstract factory is an object. I think a lot of people get these two terms confused, and start using them interchangeably. I remember that I had a hard ...
IE9 jQuery AJAX with CORS returns “Access is denied”
...own bug with jQuery. The jQuery team has "no plans to support this in core and is better suited as a plugin." (See this comment).
IE does not use the XMLHttpRequest, but an alternative object named XDomainRequest.
There is a plugin available to support this in jQuery, which can be found here:
http...
Automatically plot different colored lines
I'm trying to plot several kernel density estimations on the same graph, and I want them to all be different colors. I have a kludged solution using a string 'rgbcmyk' and stepping through it for each separate plot, but I start having duplicates after 7 iterations. Is there an easier/more efficien...
How do I limit the number of returned items?
...t to sort(), which must be an array of constraints or just one constraint, and (2) execFind() is gone, and replaced with exec() instead. Therefore, with the mongoose 3.8.1 you'd do this:
var q = models.Post.find({published: true}).sort({'date': -1}).limit(20);
q.exec(function(err, posts) {
// ...
R script line numbers at error?
If I am running a long R script from the command line (R --slave script.R), how can I get it to give line numbers at errors?
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How to get first and last day of previous month (with timestamp) in SQL Server
I could not find the solution which gives first and last day of previous month with timestamp. Hope this helps others. If there is already a solution for this problem I apologize.
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