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Mysql error 1452 - Cannot add or update a child row: a foreign key constraint fails
...was fine from the mysql point of view(both tables should use InnoDB engine and the datatype of each column should be of the same type which takes part in foreign key constraint).
The only thing that I did was to disable the foreign key check and later on enabled it after performing the foreign key o...
SQL Server NOLOCK and joins
Background: I have a performance-critical query I'd like to run and I don't care about dirty reads.
3 Answers
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Difference between Role and GrantedAuthority in Spring Security
There are concepts and implementations in Spring Security, such as the GrantedAuthority interface to get an authority to authorize/control an access.
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How to “perfectly” override a dict?
..._contains__
# free setdefault, __eq__, and so on
import pickle
# works too since we just use a normal dict
assert pickle.loads(pickle.dumps(s)) == s
I wouldn't subclass dict (or other builtins) directly. It often makes no sense, because what you actually want t...
How to drop columns by name in a data frame
I have a large data set and I would like to read specific columns or drop all the others.
11 Answers
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What exception classes are in the standard C++ library
What are the exception classes that are included in the standard C++ library, and what should they be used for? I know there are a few new C++11 exceptions, but I'm not sure what they are or where they are.
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JPA EntityManager: Why use persist() over merge()?
EntityManager.merge() can insert new objects and update existing ones.
15 Answers
15
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Can one AngularJS controller call another?
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@JoshNoe in 1/ you have two controllers (or more) and they both get one identical/shared service. Then, you have multiple ways how to communicate, some of them you mentioned. I would decide based on your specific use case. You can put the shared logic/state into the service ...
How do HTML parses work if they're not using regexp?
...s every day asking how to parse or extract something from some HTML string and the first answer/comment is always "Don't use RegEx to parse HTML, lest you feel the wrath!" (that last part is sometimes omitted).
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What is a Lambda?
...ne provide a good description of what a Lambda is? We have a tag for them and they're on the secrets of C# question, but I have yet to find a good definition and explanation of what they are in the first place.
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