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SQL Server: Get data for only the past year
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This will have very bad performance on big tables, you query will loop over every record to evaluate the year value of the date, it would be better to use a date range
– Adriaan Davel
May 30 '12 at 15:43
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grep using a character vector with multiple patterns
...attern = 'A1|A9|A6', x = myfile$Letter)
Or even more simply:
library(data.table)
myfile$Letter %like% 'A1|A9|A6'
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What are the use cases of Graph-based Databases (http://neo4j.org/)? [closed]
...nto the current blub architecture, use a graph database, or CouchDB, or BigTable, or whatever fits your app and you think is cool. It might give you an advantage, and its fun to try new things.
Whatever you chose, try not to build the database engine yourself unless you really like building databas...
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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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...
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 ...
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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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:...
MySql - Way to update portion of a string?
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I think this should work:
UPDATE table
SET field = REPLACE(field, 'string', 'anothervalue')
WHERE field LIKE '%string%';
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