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Random record from MongoDB
...llection.
db.mycoll.aggregate([{ $sample: { size: 1 } }])
If you want to select the random document(s) from a filtered subset of the collection, prepend a $match stage to the pipeline:
// Get one random document matching {a: 10} from the mycoll collection.
db.mycoll.aggregate([
{ $match: { a:...
How do I perform an insert and return inserted identity with Dapper?
...uerySingle<int>( @"
INSERT INTO [MyTable] ([Stuff]) VALUES (@Stuff);
SELECT CAST(SCOPE_IDENTITY() as int)", new { Stuff = mystuff});
Note that on more recent versions of SQL Server you can use the OUTPUT clause:
var id = connection.QuerySingle<int>( @"
INSERT INTO [MyTable] ([Stuff])
...
How to export table as CSV with headings on Postgresql?
...
@arilwan psql -c "\COPY (SELECT * FROM mytable) TO STDOUT" > mytable.csv
– Juha Palomäki
Jun 6 '19 at 16:00
...
CASCADE DELETE just once
...you want to cascade.
DELETE FROM some_child_table WHERE some_fk_field IN (SELECT some_id FROM some_Table);
DELETE FROM some_table;
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How to check if field is null or empty in MySQL?
...
Either use
SELECT IF(field1 IS NULL or field1 = '', 'empty', field1) as field1
from tablename
or
SELECT case when field1 IS NULL or field1 = ''
then 'empty'
else field1
end as field1
from tablename
...
Check if value is in select list with JQuery
...
Use the Attribute Equals Selector
var thevalue = 'foo';
var exists = 0 != $('#select-box option[value='+thevalue+']').length;
If the option's value was set via Javascript, that will not work. In this case we can do the following:
var exists = fal...
Batch file include external file for variables
...off
rem Empty the variable to be ready for label config_all
set config_all_selected=
rem Go to the label with the parameter you selected
goto :config_%1
REM This next line is just to go to end of file
REM in case that the parameter %1 is not set
goto :end
REM next label is to jump here and get a...
How to increase storage for Android Emulator? (INSTALL_FAILED_INSUFFICIENT_STORAGE)
...onfigurations". You can find that in the drop-down under the "debug" icon. Select "target", and select a preferred emulator target to launch. Then under "additional emulator command line options," add this:
-partition-size 1024
Then CLOSE the emulator (and remove any devices), and click the debug ...
How to get last N records with activerecord?
...e-wise - at least not up to Rails 3.1. SomeModel.last(5) will execute the select statement without a limit, returning all records of SomeModel to Ruby as an array, after which Ruby will pick out the last (5) elements. Efficiency-wise, currently, you want to use limit - particularly if you have pote...
How to create your own library for Android development to be used in every program you write?
...uide focuses on creating Android libraries.
Give your library a name and select a minimum SDK version for the code in the library, then click Finish.
Once the Gradle project sync completes, the library module appears in
the Project panel on the left. If you don't see the new module
fol...