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How to drop multiple columns in postgresql
I want to drop 200 columns in my table in PostgreSQL. I tried:
2 Answers
2
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Purge or recreate a Ruby on Rails database
...test:prepare for testing, or else you'll get an error like: Could not find table 'things' (ActiveRecord::StatementInvalid)
– s2t2
Feb 17 '13 at 1:49
34
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Eager load polymorphic
...d is unable to build the join without additional information.
There is no table called reviewable
To solve this issue, you need to explicitly define the relationship between Review and Shop.
class Review < ActiveRecord::Base
belongs_to :user
belongs_to :reviewable, polymorphic: true
...
Getting list of lists into pandas DataFrame
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Call the pd.DataFrame constructor directly:
df = pd.DataFrame(table, columns=headers)
df
Heading1 Heading2
0 1 2
1 3 4
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How can I send an inner to the bottom of its parent ?
...ircumstances, a better solution is to make the grandparent element display:table; and the parent element display:table-cell;vertical-align:bottom;. After doing this, you should be able to give the the child elements display:inline-block; and they will automagically flow towards the bottom of the pa...
How to subtract 30 days from the current datetime in mysql?
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SELECT * FROM table
WHERE exec_datetime BETWEEN DATE_SUB(NOW(), INTERVAL 30 DAY) AND NOW();
http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_date-add
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How to prevent form resubmission when page is refreshed (F5 / CTRL+R)
I have a simple form that submits text to my SQL table. The problem is that after the user submits the text, they can refresh the page and the data gets submitted again without filling the form again. I could redirect the user to another page after the text is submitted, but I want users to stay on ...
How to use an existing database with an Android application [duplicate]
...r getTestData() {
try {
String sql ="SELECT * FROM myTable";
Cursor mCur = mDb.rawQuery(sql, null);
if (mCur != null) {
mCur.moveToNext();
}
return mCur;
} catch (SQLException mSQLException) {
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How may I align text to the left and text to the right in the same line?
...untime that it looks bad.
What I like to do is simply create a single row table and apply the right float on the second cell. No need to apply a left-align on the first, that happens by default. This handles overlap perfectly by word-wrapping.
HTML
<table style="width: 100%;">
<tr>&...
When to use a “has_many :through” relation in Rails?
...p
# has attributes for date_joined and role
end
This introduces a new table, and eliminates the group_id column from the user's table.
The problem with this code is that you'd have to update every where else you use the user class and change it:
user.groups.first.name
# becomes
user.group_m...