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How to remove array element in mongodb?
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Try the following query:
collection.update(
{ _id: id },
{ $pull: { 'contact.phone': { number: '+1786543589455' } } }
);
It will find document with the given _id and remove the phone +1786543589455 from its contact.phone array.
You...
ssh “permissions are too open” error
I had a problem with my mac where I couldn't save any kind of file on the disk anymore.
I had to reboot OSX lion and reset the permissions on files and acls.
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Difference between one-to-many and many-to-one relationship
...ce between one-to-many and many-to-one relationship? It is only reversed, kind of?
10 Answers
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How to apply a function to two columns of Pandas dataframe
...pose I have a df which has columns of 'ID', 'col_1', 'col_2' . And I define a function :
12 Answers
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How do you check if a certain index exists in a table?
Something like this:
8 Answers
8
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Is there a MySQL option/feature to track history of changes to records?
I've been asked if I can keep track of the changes to the records in a MySQL database. So when a field has been changed, the old vs new is available and the date this took place. Is there a feature or common technique to do this?
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Correct use of Multimapping in Dapper
I'm trying to use the Multimapping feature of dapper to return a list of ProductItems and associated Customers.
6 Answers...
Postgresql aggregate array
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SELECT s.name, array_agg(g.Mark) as marks
FROM student s
LEFT JOIN Grade g ON g.Student_id = s.Id
GROUP BY s.Id
By the way, if you are using Postgres 9.1, you don't need to repeat the columns on SELECT to GROUP BY, e.g. you don't need to repeat the student name on GROUP BY. You can mere...
Database Design for Tagging
How would you design a database to support the following tagging features:
12 Answers
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T-SQL: Deleting all duplicate rows but keeping one [duplicate]
... a problem with how the rows were created I know there are some duplicates in this table.
I need to eliminate the extra rows from the perspective of the key columns. Some other columns may have slightly different data but I do not care about that. I still need to keep one of these rows however. SE...