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data.table vs dplyr: can one do something well the other can't or does poorly?
... ## data.table syntax
left_join(DT2, DT1) ## dplyr syntax
# 2. select columns while join
DT1[DT2, .(z, i.mul)]
left_join(select(DT2, x, y, mul), select(DT1, x, y, z))
# 3. aggregate while join
DT1[DT2, .(sum(z) * i.mul), by = .EACHI]
DF1 %>% group_by(x, y) %>% summarise(z = su...
Hibernate JPA Sequence (non-Id)
... an entity which has defined generated properties, it immediately issues a select afterwards to retrieve the generated values."
For properties generated on insert only, your property mapping (.hbm.xml) would look like:
<property name="foo" generated="insert"/>
For properties generated on i...
Determine .NET Framework version for dll
... |
Where-Object {$_.AttributeType.Name -eq "TargetFrameworkAttribute" } |
Select-Object -ExpandProperty ConstructorArguments |
Select-Object -ExpandProperty value
You should get something like
.NETFramework,Version=v4.5.2
...
Rails find record with zero has_many records associated [duplicate]
..._joins(:photos).where(photos: {id: nil})
which will result in SQL like:
SELECT cities.*
FROM cities LEFT OUTER JOIN photos ON photos.city_id = city.id
WHERE photos.id IS NULL
Using includes:
City.includes(:photos).where(photos: {id: nil})
will have the same result, but will result in much ug...
How to Store Historical Data
...erform an insert statement into FOO_Hist similar to: insert into FOO_HIST select * from FOO where id = @id .
13 Answers
...
compilation warning: no rule to process file for architecture i386
...w:-
Some .md, .mdown .h files are included in the Compile Sources
Step 1) Select Project Navigator
Step 2) Select your project
Step 3) Select your targetStep
Step 4) Select Build PhasesStep
Step 5) Move files which we don't want the compiler to process from Compile Sources to Copy Bundle Resource...
Is there an SQLite equivalent to MySQL's DESCRIBE [table]?
...aster table:
sqlite> CREATE TABLE foo (bar INT, quux TEXT);
sqlite> SELECT * FROM sqlite_master;
table|foo|foo|2|CREATE TABLE foo (bar INT, quux TEXT)
sqlite> SELECT sql FROM sqlite_master WHERE name = 'foo';
CREATE TABLE foo (bar INT, quux TEXT)
...
What is the difference between synchronous and asynchronous programming (in node.js)
...xamples:
// Example 1 - Synchronous (blocks)
var result = database.query("SELECT * FROM hugetable");
console.log("Query finished");
console.log("Next line");
// Example 2 - Asynchronous (doesn't block)
database.query("SELECT * FROM hugetable", function(result) {
console.log("Query finished")...
Bootstrap 3 Slide in Menu / Navbar on Mobile [closed]
...%';
$("#slide-nav").on("click", toggler, function (e) {
var selected = $(this).hasClass('slide-active');
$('#slidemenu').stop().animate({
left: selected ? menuneg : '0px'
});
$('#navbar-height-col').stop().animate({
left: selected ? sl...
SQL-Server: Error - Exclusive access could not be obtained because the database is in use
...WITH REPLACE) in optoins tab at left hand side.
Uncheck all other options.
Select source and destination database.
Click ok.
That's it.
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