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PostgreSQL LIKE query performance variations
...large variation in response times regarding LIKE queries to a particular table in my database. Sometimes I will get results within 200-400 ms (very acceptable) but other times it might take as much as 30 seconds to return results.
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How to filter NSFetchedResultsController (CoreData) with UISearchDisplayController/UISearchBar
...hedResultsController with a predicate to retrieve the data for the primary TableView. I want to make sure I'm on the right path before I change too much code. I'm confused because so many of the examples are array-based instead of CoreData.
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Database development mistakes made by application developers [closed]
... auto-incrementing fields (SQL Server, MySQL, others) or sequences (most notably Oracle).
In my opinion you should always use surrogate keys. This issue has come up in these questions:
How do you like your primary keys?
What's the best practice for primary keys in tables?
Which format of primary...
Oracle “Partition By” Keyword
...ment for every employee record. (It is as if you're de-nomalising the emp table; you still return every record in the emp table.)
emp_no dept_no DEPT_COUNT
1 10 3
2 10 3
3 10 3 <- three because there are three "dept_no = 10" records
4 20 2
5 ...
How does one reorder columns in a data frame?
...ec]
return(data)
}
Now the OP's request becomes as simple as this:
table <- data.frame(Time=c(1,2), In=c(2,3), Out=c(3,4), Files=c(4,5))
table
## Time In Out Files
##1 1 2 3 4
##2 2 3 4 5
arrange.vars(table, c("Out"=2))
## Time Out In Files
##1 1 3 2 4
##2...
Fastest way to determine if an integer is between two integers (inclusive) with known sets of values
...doing this for a very finite set of values, then you could create a lookup table. Performing the indexing might be more expensive, but if you can fit the entire table in cache, then you can remove all branching from the code, which should speed things up.
For your data the lookup table would be 12...
Advantages and disadvantages of GUID / UUID database keys
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@Matt Sheppard:
Say you have a table of customers. Surely you don't want a customer to exist in the table more than once, or lots of confusion will happen throughout your sales and logistics departments (especially if the multiple rows about the customer c...
How to understand nil vs. empty vs. blank in Ruby
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I made this useful table with all the cases:
blank?, present? are provided by Rails.
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SQLite: How do I save the result of a query as a CSV file?
...ex = False)
You can customize the query to only export part of the sqlite table to the CSV file.
You can also run a single command to export all sqlite tables to CSV files:
for table in c.execute("SELECT name FROM sqlite_master WHERE type='table';").fetchall():
t = table[0]
df = pd.read_sql...
Changing column names of a data frame
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Try setnames() in the data.table package. Use something like setnames(DT,"b","B") or setnames(DT,c("a","E"),c("A","F"))
– dwstu
Aug 11 '14 at 17:23
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