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ALTER TABLE without locking the table?
.../O overhead associated with copying the table and reconstructing secondary indexes.
see MySQL 5.6 Reference Manual -> InnoDB and Online DDL for more info.
It seems that online DDL also available in MariaDB
Alternatively you can use ALTER ONLINE TABLE to ensure that your ALTER
TABLE does n...
Java List.add() UnsupportedOperationException
...ractCollection<E> implements List<E> {
public void add(int index, E element) {
throw new UnsupportedOperationException();
}
public E set(int index, E element) {
throw new UnsupportedOperationException();
}
public E remove(int index) {
throw new...
git diff between two different files
...tterns that are supported for two files is git diff [<options>] --no-index [--] <path> <path>. git diff a b only matches commit patterns, not files.
– Doug
Jul 8 at 5:34
...
How do you track record relations in NoSQL?
I am trying to figure out the equivalent of foreign keys and indexes in NoSQL KVP or Document databases. Since there are no pivotal tables (to add keys marking a relation between two objects) I am really stumped as to how you would be able to retrieve data in a way that would be useful for normal we...
Oracle PL/SQL - How to create a simple array variable?
...xtend(); -- Extend it
array(i) := 'x';
end loop;
end;
The first index is 1 not 0.
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Where can I find documentation on formatting a date in JavaScript?
...t, show only the date.
http://www.ecma-international.org/ecma-262/7.0/index.html#sec-date.prototype.todatestring
new Date().toDateString(); // e.g. "Fri Nov 11 2016"
toISOString: Show ISO 8601 date and time.
http://www.ecma-international.org/ecma-262/7.0/index.html#sec-date.protot...
1114 (HY000): The table is full
... 1114 (HY000): The table '#sql-310a_8867d7f' is full
if you try to add an index to a table that is using the storage engine MEMORY.
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Dump a NumPy array into a csv file
...Frame(np_array).to_csv("path/to/file.csv")
if you don't want a header or index, use to_csv("/path/to/file.csv", header=None, index=None)
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What are the different usecases of PNG vs. GIF vs. JPEG vs. SVG?
...vely worse and worse.
There are also different colour depths (palettes): Indexed color and Direct color.
Indexed means that the image can only store a limited number of colours (usually 256), controlled by the author, in something called a Color Map
Direct means that you can store many thousand...
Create dynamic URLs in Flask with url_for()
...f the route','parameters (if required)')
It can be used as:
@app.route('/index')
@app.route('/')
def index():
return 'you are in the index page'
Now if you have a link the index page:you can use this:
<a href={{ url_for('index') }}>Index</a>
You can do a lot o stuff with it, f...