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Why is Dictionary preferred over Hashtable in C#?
In most programming languages, dictionaries are preferred over hashtables.
What are the reasons behind that?
19 Answers
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How to do this in Laravel, subquery where in
...>select('paper_type_id')
->from(with(new ProductCategory)->getTable())
->whereIn('category_id', ['223', '15'])
->where('active', 1);
})->get();
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Update all values of a column to lowercase
...v.mysql.com/doc/refman/5.0/en/string-functions.html#function_lower
UPDATE table_name SET tag = LOWER(tag)
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How to check Oracle database for long running queries
... object_name
/
This is a good one for finding long operations (e.g. full table scans). If it is because of lots of short operations, nothing will show up.
COLUMN percent FORMAT 999.99
SELECT sid, to_char(start_time,'hh24:mi:ss') stime,
message,( sofar/totalwork)* 100 percent
FROM v$session_l...
LISTAGG in Oracle to return distinct values
...tagg(distinct the_column, ',') within group (order by the_column)
from the_table
18c and earlier:
select listagg(the_column, ',') within group (order by the_column)
from (
select distinct the_column
from the_table
) t
If you need more columns, something like this might be what you are lo...
How do I explicitly specify a Model's table-name mapping in Rails?
I have a Model class called Countries and I want it to map to a DB table called 'cc'.
2 Answers
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cartesian product in pandas
... 6
See here for the documentation: http://pandas.pydata.org/pandas-docs/stable/merging.html#brief-primer-on-merge-methods-relational-algebra
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Is there a way to view past mysql queries with phpmyadmin?
I'm trying to track down a bug that's deleting rows in a mysql table.
13 Answers
13...
How to implement LIMIT with SQL Server?
...s for 2000 and below versions...
SELECT TOP 10 * FROM (SELECT TOP 20 FROM Table ORDER BY Id) ORDER BY Id DESC
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Sort rows in data.table in decreasing order on string key `order(-x,v)` gives error on data.table 1.
Let's say I have the following data.table in R :
3 Answers
3
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