How does one define constraints via Vapor? Here's my latest attempt:
database.schema(Thingmabob.schema)
.id()
.field("parentID", .uuid, .required, .references(Stuff.schema, .id))
.field("name", .string, .required)
.field("isDocumened", .bool, .required)
.field("value1", .uint, .required)
.field("value2", .uint)
.constraint(.custom("value2 > value1 + 1")) // << "syntax error"
.create()
Solution is two folds:
1) Seems the documentation — HA! — forgot to mention that any field mentionned in the .constraint(.custom( ... )) is set to lowercase. So if you have a field/column like .constraint(.custom("isDocumented ..."), the value in the constraint becomes isdocumented which fails to matches any column. Just beautiful!
2) Also, note that, while I'm using the .constraint() API, the framework has no idea what do to with it... I thus have to write the full statement CHECK notcamelcase > alsonotcamelcase (not just notcamelcase > alsonotcamelcase). Not sure why .constraint() isn't named .arbitrarySQLSegment() as that would've been more accurate and helpful than all that documentation I've read.
Related
I have a little problem, I want to do the typical conditional like
setting_x = Variable.get('setting_x')
variable = setting_x if setting_x else 0
But since the Airflow model throws an exception when the key doesn't exist is impossible to do it without trycatching and that's not very cool.
Is there any solution that I'm missing to solve that case? I've searched in the whole internet of course, but without a solution yet.
Thanks,
Angel
You can set the default for the Variable if it doesn't exist when you're retrieving it with the get method.
variable = Variable.get('setting_x', default_var=0)
https://github.com/apache/airflow/blob/master/airflow/models/variable.py#L127
Shorter version of the previous answer (keyword default_var omitted):
variable = Variable.get('setting_x', 0)
I have a unit test for a function that adds data (untransformed) to the database. The data to insert is given to the create function.
Do I use the input data in my asserts or is it better to specify the data that I’m asserting?
For eample:
$personRequest = [
'name'=>'John',
'age'=>21,
];
$id = savePerson($personRequest);
$personFromDb = getPersonById($id);
$this->assertEquals($personRequest['name'], $personFromDb['name']);
$this->assertEquals($personRequest['age'], $personFromDb['age']);
Or
$id = savePerson([
'name'=>'John',
'age'=>21,
]);
$personFromDb = getPersonById($id);
$this->assertEquals('John', $personFromDb['name']);
$this->assertEquals(21, $personFromDb['age']);
I think 1st option is better. Your input data may change in future and if you go by 2nd option, you will have to change assertion data everytime.
2nd option is useful, when your output is going to be same irrespective of your input data.
I got an answer from Adam Wathan by e-mail. (i took his test driven laravel course and noticed he uses the 'specify' option)
I think it's just personal preference, I like to be able to visually
skim and see "ok this specific string appears here in the output and
here in the input", vs. trying to avoid duplication by storing things
in variables." Nothing wrong with either approach in my opinion!
So i can't choose a correct answer.
I have a question, I have been reviewing some code and in one script, the authors use:
if(0){
#do something
}
Any help in what if(0) means?
The author (most likely) put the block of code in an if statement so that they could easily remove it if necessary without having to comment it out (or remove it). Similar to if(true) or if(false), you just need to change one value and it would skip that code.
Upon reviewing the code, developers should remove these kinds of statements once they've finalized all their source code not to confuse others.
Looks like something that will never be executed, since 0 = FALSE. Most probably this is a manual switch to test some code in parenthesis.
I have an entry level question which my book could not help with and I also confused a colleague. Can I use RDF without specifiying prefixes and how do I specificy the predicate in the SPARQL query?
I'm doing this in R's RRDF package but if I set up a store as
A=new.rdf(ontology=F)
add.triple(A,"Ian","sonOf","Daddy")
add.triple(A,"Ian","sonOf","Mummy")
add.triple(A,"Ian","likes","Chocolate")
I get the following message
## Error: com.hp.hpl.jena.query.QueryParseException: Lexical error
at line 1, column 40. Encountered: " " (32), after : "sonOf"
to the query
sparql.rdf(A, "select ?son ?parent where {?son sonOf ?parent}")
Can I use sonOf in this way? Do I have to set up my own Schema first? Am I doing something fundamentally wrong? Do I have to use prefixes if all my data resides on the same data source?
An RDF predicate is always a URI (technically, actually a IRI, but let's set that aside).
It can be specified as a prefixed name:
namespace:sonOf
or an IRIRef, e.g:
<http://my.namespace.com#sonOf>
but I don't think it can be given as a plain label like you are attempting.
If you use the prefixed name style, then the prefix must be defined and bound to a namespace, so that a valid URI can be constructed from your input.
(The formal grammar is given in the SPARQL Specification.)
In the rrdf R package, the following syntax seemed to work:
library(rrdf)
D = new.rdf(ontology = F)
add.triple(D, "ian", "w:likes", "food")
add.triple(D, "ian", "w:hates", "homework")
sparql.rdf(D, "select ?child ?object where {?child <w:likes> ?object.}")
sparql.rdf(D, "select ?child ?object where {?child <w:hates> ?object.}")
You thus need to used the <> in the SPARQL calls but not calls to add.triple(). This seems obvious now but confused a few of us at the time.
i think you're asking about "blank" prefixes... if so:
when you define your prefixes, you can just say something like:
PREFIX : <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
which would then be used like:
?sub :sonOf ?obj
I am trying to use ControlCommands with a .NET application (hence, these should all be standard Microsoft controls), but most of the ones that are of interest don't seem to do anything.
I am currently looking at a combobox (the drop down box). I used the "showdropdown" command to have it drop down, and it worked successfully.
I then tried to use "SelectString", but it didn't go to the string that I specified. How does the "SelectString" ControlCommand option work?
I have also tried "SetCurrentSelection".
This is the statement I used:
ControlCommand($windowName, "", "[Name:myComboBox]", "SelectString", "a")
I have also tried searching for it first with:
ControlCommand($windowName, "", "[Name:myComboBox]", "FindString", "a")
but it didn't find it either. Strange, the single character "a" is there.
If it helps, this is the control class: WindowsForms10.COMBOBOX
_GUICtrlComboBox_xxx functions also work on external controls. For example, _GUICtrlComboBox_FindString, _GUICtrlComboBox_SelectString, _GUICtrlComboBox_SetCurSel. Try those instead.
Call ControlGetHandle first, then use this handle to call the functions above.
Remember to include the GuiComboBox library, otherwise you will get an error message "Error: Unknown function name":
#include <GuiComboBox.au3>
You can send key presses to this control, like this:
ControlSend("Window title", "", "[NAME:comboBoxName]", "ComboBox value")
It works because ComboBox interprets input as a search string and selects the first item starting with this string.
Note: Because it searches the matching item as you type, there's no need to send a complete value, only the shortest substring.