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What is the meaning of the CascadeType.ALL for a @ManyToOne JPA association
...dresses {
@ManyToOne(cascade = CascadeType.REFRESH) @JoinColumn(name = "user_id")
protected User addressOwner;
}
This way you dont need to worry about using fetch in annotations. But remember when deleting the User you will also delete connected address to user object.
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Best practice for instantiating a new Android Fragment
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This approach is also documented in the android developer reference: https://developer.android.com/reference/android/app/Fragment.html
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Does SQLAlchemy have an equivalent of Django's get_or_create?
...s, it is automatically added to the session. E.g. create a book, which has user_id and user as corresponding relationship, then doing book.user=<user object> inside of create_method will add book to the session. This means that create_method must be inside with to benefit from an eventual roll...
Get started with Latex on Linux [closed]
...D$. The function $f$ is said to be \emph{continuous} on
$D$ if, for all $\epsilon > 0$ and for all $x \in D$,
there exists some $\delta > 0$ (which may depend on $x$)
such that if $y \in D$ satisfies
\[ |y - x| < \delta \]
then
\[ |f(y) - f(x)| < \epsilon. \]
One may readily verify that...
Command line to remove an environment variable from the OS level configuration
...following.
Save the PowerShell script to a file (we'll call it updateenv.ps1).
Do this from the command line: reg delete "HKCU\Environment" /v FOO /f
Run updateenv.ps1.
Close and reopen your command prompt, and you'll see that the environment variable is no longer defined.
Note, you'll probably ...
Should I be concerned about excess, non-running, Docker containers?
...r. If the container is no longer running it can still be seen with docker ps -a .
5 Answers
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Can linux cat command be used for writing text to file?
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The > characters represent the default value of $PS2; they show up automatically, and are not meant to be typed. If you have a different value for $PS2, that will show up instead.
– gbrener
Jun 5 '18 at 15:13
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How to differ sessions in browser-tabs?
...ur AJAX function check first to make sure localStorage.currently_logged_in_user_id === window.yourAppNameSpace.user_id, and if not, log in first via AJAX.
Another is race conditions: if you can switch windows fast enough to confuse it, you may end up with a relogin1->relogin2->ajax1->ajax2...
What's the difference between belongs_to and has_one?
...s. We can say that a User "has" a Profile because the profiles table has a user_id column. If there was a column called profile_id on the users table, however, we would say that a Profile has a User, and the belongs_to/has_one locations would be swapped.
here is a more detailed explanation.
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sqlalchemy: how to join several tables by one query?
...om"
).all()
One note about that...
query.join(Address, User.id==Address.user_id) # explicit condition
query.join(User.addresses) # specify relationship from left to right
query.join(Address, User.addresses) # same, with explicit target
query.join('addresses') ...