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Can I add a UNIQUE constraint to a PostgreSQL table, after it's already created?
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Also documented in the postgres docs (an excellent resource, plus easy to read, too).
ALTER TABLE tablename ADD CONSTRAINT constraintname UNIQUE (columns);
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What is __pycache__?
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__pycache__ is a folder containing Python 3 bytecode compiled and ready to be executed.
I don't recommend routinely deleting these files or suppressing creation during development as it may hurt performance. Just have a recursive command ready (see below) to clean up when needed as bytecod...
Setting dynamic scope variables in AngularJs - scope.
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Just to add into alread given answers, the following worked for me:
HTML:
<div id="div{{$index+1}}" data-ng-show="val{{$index}}">
Where $index is the loop index.
Javascript (where value is the passed parameter to the function and it ...
What is the difference between exit and return? [duplicate]
...urse when it's your program do whatever you prefer or believe is easier to read.
– kriss
Apr 3 '19 at 9:13
@kriss: thi...
Tablet or Phone - Android
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More info : http://groups.google.com/group/android-developers/browse_thread/thread/d6323d81f226f93f
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Pandas - Get first row value of a given column
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I'm looping through a bunch of .csv files and reading the first value of a certain column in each. For some reason which I can't explain instead of returning the value this sometimes returns the index along with the value which messes up processing. I resorted to df.col....
Creating an object: with or without `new` [duplicate]
This is probably a basic question, and might have already been asked (say, here ); yet I still don't understand it. So, let me ask it.
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Error: Tablespace for table xxx exists. Please DISCARD the tablespace before IMPORT
...the table with the exact same name I got a message saying that the table already exists(for which I deleted the .idb file)...after the above action a new orphaned .idb file was created in the dir...very strange...I really do not know what to assume.
– Dimitris Papageorgiou
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Maven is not working in Java 8 when Javadoc tags are incomplete
...ting Javadocs. You need to turn this off for Java 8 as specified in this thread. You'll have to add this to your maven configuration:
<profiles>
<profile>
<id>java8-doclint-disabled</id>
<activation>
<jdk>[1.8,)</jdk>
</activation>...
Difference between return and exit in Bash functions
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However, echo fnord | while read x; do exitfunc; done; echo "still here" will print "still here". It seems that only the while sub-shell is exited in this scenario.
– tripleee
Dec 11 '13 at 9:30
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