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UnmodifiableMap (Java Collections) vs ImmutableMap (Google) [duplicate]
...odifiableMap.get("E"); // Will return "F".
In contrast to that, the ImmutableMap of Guava is really immutable: It is a true copy of a given map, and nobody may modify this ImmutableMap in any way.
Update:
As pointed out in a comment, an immutable map can also be created with the standard API ...
Nearest neighbors in high-dimensional data?
...set of points in a high-dimensional space into a set of bins, i.e., a hash table [1][3]. But unlike traditional hashes, a locality-sensitive hash places nearby points into the same bin.
LSH has some huge advantages. First, it is simple. You just compute the hash for all points in your database, the...
Rails find record with zero has_many records associated [duplicate]
... do includes it does a join. In a SQL join, you get all the fields of both tables (in this case cities and photos) for each row unless you change the projection of the query. So, he's using that to his advantage to check whether a required database identifier is present. If it's not, then there was ...
How to fix the Hibernate “object references an unsaved transient instance - save the transient insta
... I got this issue specifically when I used @Inheritance, in this case TABLE_PER_CLASS, I was referencing a subclass. CascadeType.ALL fixed it.
– Jim ReesPotter
Mar 17 '18 at 21:08
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What is the difference between SQL, PL-SQL and T-SQL?
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Correction: SQL is a language to operate on tables for which SQL itself provides the definition. The SQL Standard avoids the words 'set' and 'relation' and their derivatives. SQL tables are not sets.
– onedaywhen
Nov 25 '11 at 12:...
How to implement a unique index on two columns in rails
I have a table and I'm trying to add a unique index on two columns. Those columns are also indexed. So my question is if I just can remove the indexes who were just for one column or if I have to use all three indexes:
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How to run `rails generate scaffold` when the model already exists?
... does generate the view layer but it doesn't include the model attributes (table columns) and you have to add those by hand. Anybody know of a fix for this? I am on Rails 3.2.8.
– aaronbartell
Dec 3 '12 at 22:10
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Multiple queries executed in java in single statement
... it is possible to execute something like this using JDBC.
"SELECT FROM * TABLE;INSERT INTO TABLE;"
Yes it is possible. There are two ways, as far as I know. They are
By setting database connection property to allow multiple queries,
separated by a semi-colon by default.
By calling a stored pro...
How can I avoid Java code in JSP files, using JSP 2?
...fway, all you get is a blank page.
Testability: scriptlets are not unit-testable.
Maintainability: per saldo more time is needed to maintain mingled/cluttered/duplicated code logic.
Sun Oracle itself also recommends in the JSP coding conventions to avoid use of scriptlets whenever the same functio...
What does the [Flags] Enum Attribute mean in C#?
...ean, I prefer to have the full int in source code. If I have a column on a table in the database called MyEnum that stores a value of one of the enums, and a record has 131,072, I would need to get out my calculator to figure out that that corresponds to the enum with the value 1<<17. As oppos...