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How can I call a custom Django manage.py command directly from a test driver?
...for a Django manage.py command that does a backend operation on a database table. How would I invoke the management command directly from code?
...
Factors in R: more than an annoyance?
...a pain, but my theory is that 90% of why they're a pain is because in read.table and read.csv, the argument stringsAsFactors = TRUE by default (and most users miss this subtlety). I say they are useful because model fitting packages like lme4 use factors and ordered factors to differentially fit mod...
PDO's query vs execute
... execution. Which means you can do:
$sth = $db->prepare("SELECT * FROM table WHERE foo = ?");
$sth->execute(array(1));
$results = $sth->fetchAll(PDO::FETCH_ASSOC);
$sth->execute(array(2));
$results = $sth->fetchAll(PDO::FETCH_ASSOC);
They generally will give you a performance impr...
Test if lists share any items in python
...as such:
bool(set(a) & set(b))
Because sets are stored using a hash table in Python, searching them is O(1) (see here for more information about complexity of operators in Python). Theoretically, this is O(n+m) on average for n and m objects in lists a and b. But 1) it must first create sets ...
Rails 3 migrations: Adding reference column?
...class AddUserToTester < ActiveRecord::Migration
def change
change_table :testers do |t|
t.references :user, index: true
end
end
def down
change_table :testers do |t|
t.remove :user_id
end
end
end
c.f.: http://apidock.com/rails/ActiveRecord/ConnectionAdapters...
Why does Sql Server keep executing after raiserror when xact_abort is on?
...nd executes a stored procedure that we assume will fail:
assume we have a table [dbo].[Errors] to hold errors
assume we have a stored procedure [dbo].[AssumeThisFails] which will fail when we execute it
-- first lets build a temporary table to hold errors
if (object_id('tempdb..#RAISERRORS') is nu...
Why should I capitalize my SQL keywords? [duplicate]
...nk the latter is more readable. You can easily separate the keywords from table and column names, etc.
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IN vs OR in the SQL WHERE Clause
...tion Plan.
I tried it with Oracle, and it was exactly the same.
CREATE TABLE performance_test AS ( SELECT * FROM dba_objects );
SELECT * FROM performance_test
WHERE object_name IN ('DBMS_STANDARD', 'DBMS_REGISTRY', 'DBMS_LOB' );
Even though the query uses IN, the Execution Plan says that it u...
Versioning SQL Server database
...N to N+1. (These go in your version control system.) A _version_history_ table, something like
create table VersionHistory (
Version int primary key,
UpgradeStart datetime not null,
UpgradeEnd datetime
);
gets a new entry every time an upgrade script runs which corresponds to th...
MySQL root access from all hosts
...on a remote Ubuntu machine. The root user is defined in the mysql.user table this way:
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