大约有 18,357 项符合查询结果（耗时：0.0208秒） [XML]
How to determine if a record is just created or updated in after_save
...king to use this for an after_save callback.
A simpler solution is to use id_changed? (since it won't change on update) or even created_at_changed? if timestamp columns are present.
Update: As @mitsy points out, if this check is needed outside of callbacks then use id_previously_changed?. See docs...
When to use .First and when to use .FirstOrDefault with LINQ?
... @driis - I'd imagine we can use the mantra of the exceptional exception guideline when choosing between First and FirstOrDefault. Thanks for the clear answer.
– Metro Smurf
Jun 21 '09 at 21:21
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How do you do a limit query in JPQL or HQL?
...tMaxResults().
So if it worked in Hibernate 2, it seems that was by coincidence, rather than by design. I think this was because the Hibernate 2 HQL parser would replace the bits of the query that it recognised as HQL, and leave the rest as it was, so you could sneak in some native SQL. Hibernate ...
Check if checkbox is checked with jQuery
How can I check if a checkbox in a checkbox array is checked using the id of the checkbox array?
23 Answers
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How to declare a variable in a PostgreSQL query
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This is ideal for when I have a migration script where I want to import some relational data. Obviously I won't know the sequence id the relational data is given.
– Relequestual
Feb 13 '15 at 9:...
Jenkins Host key verification failed
...tal: The remote end hung up unexpectedly
– A. M. Mérida
Mar 4 '13 at 8:40
6
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廉价共享存储解决方案2-drbd+cman+gfs2 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...lic/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
a9:8a:3a:3d:64:eb:0b:de:94:a5:92:e4:ba:5d:f3:de root@gfs_1
The key's rand...
mongodb count num of distinct values per field/key
...
},
{ $unwind: "$keywords" },
{
$group: {
_id: {$toLower: '$keywords'},
count: { $sum: 1 }
}
},
{
$match: {
count: { $gte: 2 }
}
},
{ $sort : { count : -1} },
{ $limit : 100 }
]);
that give result s...
What is the difference between a stored procedure and a view?
...nd why to use each.
Say I have two tables:
tbl_user, with columns: user_id, user_name, user_pw
tbl_profile, with columns: profile_id, user_id, profile_description
So, if I find myself querying from those tables A LOT... instead of doing the join in EVERY piece of SQL, I would define a view like...
Why can't Python parse this JSON data?
...
Your data is not valid JSON format. You have [] when you should have {}:
[] are for JSON arrays, which are called list in Python
{} are for JSON objects, which are called dict in Python
Here's how your JSON file should look:
{
"maps": [...