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SQL Add foreign key to existing column

... Error indicates that there is no UserID column in your Employees table. Try adding the column first and then re-run the statement. ALTER TABLE Employees ADD CONSTRAINT FK_ActiveDirectories_UserID FOREIGN KEY (UserID) REFERENCES ActiveDirectories(id); ...
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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...
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How to persist a property of type List in JPA?

... String> { private static final String SPLIT_CHAR = ";"; @Override public String convertToDatabaseColumn(List<String> stringList) { return String.join(SPLIT_CHAR, stringList); } @Override public List<String> convertToEntityAttribute(String string) { ...
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The relationship could not be changed because one or more of the foreign-key properties is non-nulla

I am getting this error when I GetById() on an entity and then set the collection of child entities to my new list which comes from the MVC view. ...
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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 ...
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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

... 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:...
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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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...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...