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Difference Between One-to-Many, Many-to-One and Many-to-Many?
Ok so this is probably a trivial question but I'm having trouble visualizing and understanding the differences and when to use each. I'm also a little unclear as to how concepts like uni-directional and bi-directional mappings affect the one-to-many/many-to-many relationships. I'm using Hibernate ri...
Can table columns with a Foreign Key be NULL?
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Yes, you can enforce the constraint only when the value is not NULL. This can be easily tested with the following example:
CREATE DATABASE t;
USE t;
CREATE TABLE parent (id INT NOT NULL,
PRIMARY KEY (id)
) ENGINE=INNODB;
CREATE TABLE...
How to add url parameters to Django template url tag?
In my view to get url parameters like this:
6 Answers
6
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CodeIgniter activerecord, retrieve last insert id?
Are there any options to get the last insert id of a new record in CodeIgniter?
11 Answers
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How to copy a row and insert in same table with a autoincrement field in MySQL?
In MySQL I am trying to copy a row with an autoincrement column ID=1 and insert the data into same table as a new row with column ID=2 .
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How to do an update + join in PostgreSQL?
..._list ]
[ WHERE condition | WHERE CURRENT OF cursor_name ]
[ RETURNING * | output_expression [ [ AS ] output_name ] [, ...] ]
In your case I think you want this:
UPDATE vehicles_vehicle AS v
SET price = s.price_per_vehicle
FROM shipments_shipment AS s
WHERE v.shipment_id = s.id
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Grouped LIMIT in PostgreSQL: show the first N rows for each group?
... edited Aug 11 '16 at 9:08
ngspkinga
42155 silver badges1616 bronze badges
answered May 19 '11 at 19:55
DaveDa...
How to develop a soft keyboard for Android? [closed]
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Some tips:
Read this tutorial: Creating an Input Method
clone this repo: LatinIME
About your questions:
An inputMethod is basically an Android Service, so yes, you can do HTTP and all the stuff you can do in a Service.
You can open Activities and dialogs fr...
MySQL foreign key constraints, cascade delete
I want to use foreign keys to keep the integrity and avoid orphans (I already use innoDB).
3 Answers
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Set selected index of an Android RadioGroup
Is there a way to set the selected index of a RadioGroup in android, other than looping through the child radiobuttons and selecting checking the radio button at the selected index?
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