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MongoDB, remove object from array
... yup, my syntax was wrong. Thanks! Also tried without the upset and multi options and that worked as well.
– lostintranslation
Mar 26 '13 at 20:25
12
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How to get the unique ID of an object which overrides hashCode()?
...iginal memory address for this object, but that's an implementation detail and you shouldn't rely on it.
EDIT: Answer modified following Tom's comment below re. memory addresses and moving objects.
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Find object in list that has attribute equal to some value (that meets any condition)
... None)
This gets the first item from the list that matches the condition, and returns None if no item matches. It's my preferred single-expression form.
However,
for x in test_list:
if x.value == value:
print("i found it!")
break
The naive loop-break version, is perfectly Pytho...
MongoDB atomic “findOrCreate”: findOne, insert if nonexistent, but do not update
as the title says, I want to perform a find (one) for a document, by _id, and if doesn't exist, have it created, then whether it was found or was created, have it returned in the callback.
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MySQL Creating tables with Foreign Keys giving errno: 150
...e the primary keys in 2 other tables, but I am getting an errno: 150 error and it will not create the table.
20 Answers
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SQL Add foreign key to existing column
If I am using the following SQL command in SQL Server 2008 to update a table with a foreign key constraint:
6 Answers
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Android ViewPager with bottom dots
...ly viewpager with tablayout.
Your main Layout:
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v4.view.Vi...
How do I specify unique constraint for multiple columns in MySQL?
... For those people using MySQL workbench: go to the Indexes tab and select UNIQUE as your type. Give your index a name and check the appropriate columns under the section "Index Columns"
– Pakman
Jun 3 '13 at 20:42
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Reference alias (calculated in SELECT) in WHERE clause
...x (or costly to calculate) you should probably consider a computed column (and perhaps persisted) instead, especially if a lot of queries refer to this same expression.
PS your fears seem unfounded. In this simple example at least, SQL Server is smart enough to only perform the calculation once, ev...
How can I use UUIDs in SQLAlchemy?
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The sqlalchemy postgres dialect supports UUID columns. This is easy (and the question is specifically postgres) -- I don't understand why the other answers are all so complicated.
Here is an example:
from sqlalchemy.dialects.postgresql import UUID
from flask_sqlalchemy import SQLAlchemy
impo...