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Can a foreign key be NULL and/or duplicate?
.... So your proposal table would have two foreign keys, one with the client ID and one with the sales rep ID. However, at the time the record is created, a sales rep is not always assigned (because no one is free to work on it yet), so the client ID is filled in but the sales rep ID might be null. ...
MySQL Multiple Joins in one query?
... dashboard_data.headline, dashboard_data.message, dashboard_messages.image_id, images.filename
FROM dashboard_data
INNER JOIN dashboard_messages
ON dashboard_message_id = dashboard_messages.id
INNER JOIN images
ON dashboard_messages.image_id = images.image_id
However be ...
SQL Server indexes - ascending or descending, what difference does it make?
...y Optimiser's point of view.
For the table definition
CREATE TABLE T1( [ID] [int] IDENTITY NOT NULL,
[Filler] [char](8000) NULL,
PRIMARY KEY CLUSTERED ([ID] ASC))
The Query
SELECT TOP 10 *
FROM T1
ORDER BY ID DESC
Uses an ordered scan with scan direction BAC...
How Do I Fetch All Old Items on an RSS Feed?
...hoops! Found it. This link details it ws-dl.blogspot.fr/2013/07/… Specifically, you'd do something like this web.archive.org/web/timemap/link/$url Thanks!
– The1nk
Jul 20 '16 at 13:26
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Typescript: difference between String and string
...a new distinction introduced by TypeScript - I don't think it's helpful to call one a JS type and the other a TS type.
– Joe Lee-Moyet
Jan 25 '16 at 13:46
...
How to transfer some data to another Fragment?
...lass implements Serializable {
private static final long serialVersionUID = -2163051469151804394L;
private int id;
private String created;
}
In you FromFragment:
Bundle args = new Bundle();
args.putSerializable(TAG_MY_CLASS, myClass);
Fragment toFragment = new ToFragment();
toFragment...
How do SO_REUSEADDR and SO_REUSEPORT differ?
...BSD socket implementation is the mother of all socket implementations. Basically all other systems copied the BSD socket implementation at some point in time (or at least its interfaces) and then started evolving it on their own. Of course the BSD socket implementation was evolved as well at the sam...
Is python's sorted() function guaranteed to be stable?
...on 2.4 effectively make the point that sorted() first creates a list, then calls sort() on it, providing you with the guarantee you need though not in the "official" docs. You could also just check the source, if you're really concerned.
...
What do (lambda) function closures capture?
...
Option 2 resembles what functional languages would call a "Curried function."
– Crashworks
Sep 20 '11 at 2:15
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MySQL Cannot Add Foreign Key Constraint
...the parent column exactly. For example, since medicalhistory.MedicalHistoryID is an INT, Patient.MedicalHistory also needs to be an INT, not a SMALLINT.
Also, you should run the query set foreign_key_checks=0 before running the DDL so you can create the tables in an arbitrary order rather than need...