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static allocation in java - heap, stack and permanent generation
...ing a lot on memory allocation schemes in java, and there have been many doubts as I have been reading from various sources. I have collected my concepts, and I would request to go through all of the points and comment on them. I came to know that memory allocation is JVM specific, so I must say bef...
Cannot change column used in a foreign key constraint
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The type and definition of foreign 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...
How to send a JSON object using html form data
...ify it.
var formData = JSON.stringify($("#myForm").serializeArray());
You can use it later in ajax. Or if you are not using ajax; put it in hidden textarea and pass to server. If this data is passed as json string via normal form data then you have to decode it using json_decode. You'll then get...
What is a memory fence?
What is meant by using an explicit memory fence?
4 Answers
4
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Where to place $PATH variable assertions in zsh?
I love zsh , but I am not sure where to place my $PATH and other variable assertions? I find that they are scattered between the files .zshrc .zprofile .bashrc .bash_profile , and sometimes doubled.
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Difference between RegisterStartupScript and RegisterClientScriptBlock?
Is the only difference between the RegisterStartupScript and the RegisterClientScriptBlock is that RegisterStartupScript puts the javascript before the closing </form> tag of the page and RegisterClientScriptBlock puts it right after the starting <form> tag of the page?
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Can git automatically switch between spaces and tabs?
I use tabs for indentation in my python programs, but I would like to collaborate (using git) with people who use spaces instead.
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How update the _id of one MongoDB Document?
I want update an _id field of one document. I know it's not a really good pratice. But with some technical reason, I need update it. If I try to update it I get:
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Purpose of ESI & EDI registers?
What is the actual purpose and use of the EDI & ESI registers in assembler?
5 Answers
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B-Tree vs Hash Table
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You can only access elements by their primary key in a hashtable.
This is faster than with a tree algorithm (O(1) instead of log(n)), but you cannot select ranges (everything in between x and y).
Tree algorithms support this in...