大约有 37,000 项符合查询结果（耗时：0.0259秒） [XML]
LEFT OUTER joins in Rails 3
... the :include option, which will perform an
INNER JOIN on the associated table(s), or an array containing a
mixture of both strings and named associations.
If the value is a
string, then the records will be returned read-only since they will
have attributes that do not correspond to th...
ActiveRecord: size vs count
...e way to go if you are using the data.
Example: Summary of a fully loaded table, titles of displayed data, etc.
size
It checks if the data was loaded (i.e. already in rails) if so, then just count it, otherwise it calls count. (plus the pitfalls, already mentioned in other entries).
def size
l...
String literals and escape characters in postgresql
Attempting to insert an escape character into a table results in a warning.
5 Answers
...
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...
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...
How to do paging in AngularJS?
...y current use and has a thorough test spec to accompany it.
View
<!-- table here -->
<pagination
ng-model="currentPage"
total-items="todos.length"
max-size="maxSize"
boundary-links="true">
</pagination>
<!-- items/page select here if you like -->
Controller
...
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 ...
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...
MySQL root access from all hosts
...on a remote Ubuntu machine. The root user is defined in the mysql.user table this way:
9 Answers
...