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find vs find_by vs where
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Use whichever one you feel suits your needs best.
The find method is usually used to retrieve a row by ID:
Model.find(1)
It's worth noting that find will throw an exception if the item is not found by the attribute that you supply. Use where (as described below, which will return an empty arr...
What is the difference between the Eclipse Package Explorer and the Eclipse Project Explorer?
It seems to me these two views are virtually identical, especially since Galileo. Is this true, or am I missing out on some features of one or the other?
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Insert new column into table in sqlite?
... ADD COLUMN COLNew {type};
Second, and more complicatedly, but would actually put the column where you want it, would be to rename the table:
ALTER TABLE {tableName} RENAME TO TempOldTable;
Then create the new table with the missing column:
CREATE TABLE {tableName} (name TEXT, COLNew {type} DE...
Running a Haskell program on the Android OS
...ndroid NDK which comes with a GCC port for ARM architectures. JHC can trivially do this with a very small inf style file which describes the platform (word size, c-compiler, etc) I've done this with the Wii homebrew dev kit and it was quite easy. However jhc still has some stability issues with comp...
How can I search for a multiline pattern in a file?
I needed to find all the files that contained a specific string pattern. The first solution that comes to mind is using find piped with xargs grep :
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how to emulate “insert ignore” and “on duplicate key update” (sql merge) with postgresql?
...gsql-control-structures.html, example 40-2 right at the bottom.
That's usually the easiest way. You can do some magic with rules, but it's likely going to be a lot messier. I'd recommend the wrap-in-function approach over that any day.
This works for single row, or few row, values. If you're deali...
Handling an empty UITableView. Print a friendly message
... change the height of your cell to accommodate the empty message. This is all doable but it seems like band-aid on top of band-aid.
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Is there an equivalent for the Zip function in Clojure Core or Contrib?
... a collection of zipWith (zipWith3, zipWith4, ...) functions, because they all need to be of a specific type; in particular, the number of input lists they accept needs to be fixed. (The zip, zip2, zip3, ... family can be regarded as a specialisation of the zipWith family for the common use case of ...
What is the difference between single and double quotes in SQL?
...d to indicate the beginning and end of a string in SQL. Double quotes generally aren't used in SQL, but that can vary from database to database.
Stick to using single quotes.
That's the primary use anyway. You can use single quotes for a column alias — where you want the column name you referen...
Further understanding setRetainInstance(true)
What exactly happens when you call setRetainInstance(true) on a Fragment ? The documentation is virtually non-existent and this seems like a very important function. Specifically I want to know how much of this sequence (that I made up) is true:
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