大约有 18,361 项符合查询结果（耗时：0.0235秒） [XML]
Combine two ActiveRecord::Relation objects
...ates being able to use any ActiveRecord methods on them afterwards, but I didn't need to. I did this:
name_relation = first_name_relation + last_name_relation
Ruby 1.9, rails 3.2
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What's the difference between session.persist() and session.save() in Hibernate?
... transient instance persistent.
However, it doesn't guarantee that the
identifier value will be assigned to
the persistent instance immediately,
the assignment might happen at flush
time. The spec doesn't say that, which
is the problem I have with persist().
persist() also guarante...
findViewByID returns null
...days on something so trivial. I moved setContentView() above the findViewById() call and that did t he trick. thanks!
– agentcurry
Jan 26 '12 at 20:35
2
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Foreign key constraint may cause cycles or multiple cascade paths?
...lter your design (or doing so would compromise things) then you should consider using triggers as a last resort.
FWIW resolving cascade paths is a complex problem. Other SQL products will simply ignore the problem and allow you to create cycles, in which case it will be a race to see which will ove...
How to open a second activity on click of button in android app
I am learning to build android applications and I need some specific help. I can't seem to get my head around which bits of template code I am required to change, and which bits are static.
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sqlalchemy unique across multiple columns
... that represents locations. Locations "belong" to customers. Locations are identified by a unicode 10 character code. The "location code" should be unique among the locations for a specific customer.
...
MongoDB and “joins” [duplicate]
...s to do it manually, as you have almost described. Just save a document's _id in another document's other_id, then write your own function to resolve the relationship. The other solution is to use DBRefs as described on the manual page above, which will make MongoDB resolve the relationship client-s...
The object 'DF__*' is dependent on column '*' - Changing int to double
...se DB migrations of my framework (Laravel) and dropColumn there? I have no idea how to drop the constraint which has mysterious name, autogenerated by SQL server :(
– JustAMartin
Feb 15 '16 at 16:00
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SQL update from one Table to another based on a ID match
... Sales_Import SI
INNER JOIN
RetrieveAccountNumber RAN
ON
SI.LeadID = RAN.LeadID;
MySQL and MariaDB
UPDATE
Sales_Import SI,
RetrieveAccountNumber RAN
SET
SI.AccountNumber = RAN.AccountNumber
WHERE
SI.LeadID = RAN.LeadID;
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How to return an empty ActiveRecord relation?
...
A more portable solution that doesn't require an "id" column and doesn't assume there won't be a row with an id of 0:
scope :none, where("1 = 0")
I'm still looking for a more "correct" way.
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