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Cannot change column used in a foreign key constraint
...eign key field and reference must be equal.
This means your foreign key disallows changing the type of your field.
One solution would be this:
LOCK TABLES
favorite_food WRITE,
person WRITE;
ALTER TABLE favorite_food
DROP FOREIGN KEY fk_fav_food_person_id,
MODIFY person_id SMALLIN...
if, elif, else statement issues in Bash
...to if [ "$seconds" -eq 0 ];then ... fi ]. @LeiYang man testis what you actually looking for
– Melicerte
May 15 '19 at 9:33
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How to return a result (startActivityForResult) from a TabHost Activity?
I have 3 classes in my example:
Class A, the main activity. Class A calls a startActivityForResult:
5 Answers
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What are the differences between the BLOB and TEXT datatypes in MySQL?
...nstead of using blob or text ? because in memory calculating, varchar is really simple, for example create table website( website_name varchar(30) ) and then we fill the website_name "stackoverflow" so the memory needed is 13byte
– nencor
Jul 24 '12 at 9:36
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What does set -e mean in a bash script?
...shell functions, so if you have functions, set -o errtrace or set -E will allow you to just set the trap once and apply it globally.
– ykay
Jul 17 '15 at 18:21
32
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Select something that has more/less than x character
...e LENGTH function to the EmployeeName column). In Oracle, and probably in all other RDBMSs, this means that a regular index on EmployeeName will be useless to answer this query; the database will do a full table scan, which can be really costly.
However, various databases offer a function indexes ...
iPad browser WIDTH & HEIGHT standard
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Ericson578: These are all for ipad 1.
– Paul Rademacher
Apr 30 '12 at 21:39
2
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How to add a second css class with a conditional value in razor MVC 4
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Personally I prefer the trivial logic, having a getDetailCssClass method means that your Model is aware of your View, breaking down that abstraction. I would add an HasDetails method to the Model to reduce the logic required in the...
Capture screenshot of active window?
I am making a screen capturing application and everything is going fine. All I need to do is capture the active window and take a screenshot of this active window. Does anyone know how I can do this?
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Run java jar file on a server as background process
...on
[Service]
ExecStart=/usr/bin/java -jar /web/server.jar
User=user
[Install]
WantedBy=multi-user.target
Step 4:
Run your service
as super user
$ systemctl start whatever_you_want.service # starts the service
$ systemctl enable whatever_you_want.service # auto starts the service
$ systemctl ...