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How to add an auto-incrementing primary key to an existing table, in PostgreSQL?
...h this solution is that if the table already contains rows then you get an error: SQL Error [23502]: ERROR: column "id" contains null values
– isapir
Mar 7 '18 at 16:30
3
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Bash, no-arguments warning, and case decisions
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thanks, of course! and last thing, how can i turn off error messages ib the script, so they are not shown to the shell?
– Open the way
Mar 11 '10 at 20:04
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Django: Why do some model fields clash with each other?
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Thanks, the error message was not obvious to me either, but your explanation about the reverse relation was very helpful.
– ruquay
May 26 '11 at 22:45
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Append integer to beginning of list in Python [duplicate]
...nning with the variable and ending with the list.
Writing a + list I get errors. The compiler handles a as integer, thus I cannot use append, or extend either.
How would you do this?
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What are some better ways to avoid the do-while(0); hack in C++?
...es something that can be solved with RAII. Maybe I should have said "issue error" or some such instead.
– Mats Petersson
Aug 29 '13 at 10:15
25
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What happens to an open file handle on Linux if the pointed file gets moved or deleted
...lug) then the file handle won't be valid any more and is likely to give IO/error on any operation. You still have to close it though. This is going to be true even if the device is plugged back in, as it's not sensible to keep a file open in this case.
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How to print to the console in Android Studio?
...nd specify the category of message.
The main options are:
DEBUG: Log.d
ERROR: Log.e
INFO: Log.i
VERBOSE: Log.v
WARN: Log.w
You print a message by using a Log statement in your code, like the following example:
Log.d("myTag", "This is my message");
Within Android Studio, you can search for...
Can't find the 'libpq-fe.h header when trying to install pg gem
...SQL, but the problem is installing the pg gem. It gives me the following error:
41 Answers
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Value cannot be null. Parameter name: source
...one a while back, and the answer isn't necessarily what you'd expect. This error message often crops up when your connection string is wrong.
At a guess, you'll need something like this:
<connectionStrings>
<add name="hublisherEntities" connectionString="Data Source=localhost;Initial ...
Excel “External table is not in the expected format.”
...code shown below. I get an "External table is not in the expected format." error unless I have the file already open in Excel. In other words, I have to open the file in Excel first before I can read if from my C# program. The xlsx file is on a share on our network. How can I read the file without h...