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Nullable Foreign Key bad practice?
...y key in that link table the relationship is still 1..n. There can only be one entry in that link table per order.
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scheduleAtFixedRate vs scheduleWithFixedDelay
...g coffee
02:10: Finish making coffee
If I schedule with a fixed delay of one hour, I'd have:
00:00: Start making coffee
00:10: Finish making coffee
01:10: Start making coffee
01:20: Finish making coffee
02:20: Start making coffee
02:30: Finish making coffee
Which one you want depends on your ta...
HTML5 best practices; section/header/aside/article elements
... the "best practices". Tags like section/headers/article are new, and everyone has different opinions about when/where you should use these tags. So what do you guys think of the following layout and code?
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What's the best practice for primary keys in tables?
When designing tables, I've developed a habit of having one column that is unique and that I make the primary key. This is achieved in three ways depending on requirements:
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Should each and every table have a primary key?
...e link. Thus you ensure that you don't have two or more records describing one link.
Besides the logical consistency issues, most RDBMS engines will benefit from including these fields in a unique index.
And since any primary key involves creating a unique index, you should declare it and get both...
JPA EntityManager: Why use persist() over merge()?
EntityManager.merge() can insert new objects and update existing ones.
15 Answers
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Entity Framework vs LINQ to SQL
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This answer is obsolete. Now Linq to SQL supports one2many mapping
– George Lanetz
Dec 29 '15 at 13:18
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Java: Multiple class declarations in one file
...define multiple top level classes in a single file, providing that at most one of these is public (see JLS §7.6 ). See below for example.
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What exactly does git's “rebase --preserve-merges” do (and why?)
...ase, git with --preserve-merges first identifies a list of commits made in one part of the commit graph, and then replays those commits on top of another part. The differences with --preserve-merges concern which commits are selected for replay and how that replaying works for merge commits.
To be ...
What is “entropy and information gain”?
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I assume entropy was mentioned in the context of building decision trees.
To illustrate, imagine the task of learning to classify first-names into male/female groups. That is given a list of names each labeled with either m or f, we want to learn a m...