I would like to have multiple level single table inheritance, is this possible? For example, if I have a billable_items table that I would like to split into client and consultants, and add a second level to the consultants, like 'wage', 'referral', 'transportation', etc, would this be possible?
Solved: as the documentation states, you just need to define the entire inheritance hierarchy in the discriminator map of the TOPMOST class. For any 2nd level base/abstract parent classes, you would NOT include them in the discriminator map, just make sure you add the entity annotation.
Related
I'm reading EcmaScript specification.
At 9.2.12, there are:
11.Let varNames be the VarDeclaredNames of code.
12.Let varDeclarations be the VarScopedDeclarations of code.
And at 13.1.5 and 13.1.6:
13.1.5 Static Semantics: VarDeclaredNames
Statement :
EmptyStatement
ExpressionStatement
ContinueStatement
BreakStatement
ReturnStatement
ThrowStatement
DebuggerStatement
Return a new empty List.
13.1.6 Static Semantics: VarScopedDeclarations
Statement :
EmptyStatement
ExpressionStatement
ContinueStatement
BreakStatement
ReturnStatement
ThrowStatement
DebuggerStatement
Return a new empty List.
They look like the same.So I want to know what's the difference between VarDeclaredNames and VarScopedDeclarations ? Can you give me some examples?
Thanks.
Those two static semantic rules search the AST for the same kinds of things: VariableDeclarations, ForBindings, FunctionDeclarations and GeneratorDeclarations. There's a lot of duplication (especially in methodology) indeed.
However, as #loganfsmyth mentions in the comments, they do return different data - different types of lists. While VarDeclaredNames returns a list of names (strings), VarScopedDeclarations does return a list of declarations (i.e. AST nodes).
This is apparent in the sections where something is actually appended to the lists: §13.3.2.2, §13.7.4.5, §13.7.5.7, and §13.2.9 all do refer to the BoundNames of the respective element, while §13.3.2.3, §13.7.4.6, §13.7.5.8, and §13.2.10 do refer to the respective declaration itself.
Why is this distinction needed? The VarDeclaredNames are used to create the bindings in the scope, while the VarScopedDeclarations are used to find the function declarations to create (and initialise the bindings with those values).
Could it have been simpler? Yes, surely - for lexical declarations, the scope initialisation description just iterates the declarations and gets the BoundNames of each. You might want to submit a bug to spec authors to use this approach for function-level declarations as well. See issue 1203 discussing this.
When I sign an XML document I get:
<ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#" Id="xmldsig-f62dafae-6983-4b97-9b52-3f24c6960c43">
....
<ds:SignatureValue Id="xmldsig-f62dafae-6983-4b97-9b52-3f24c6960c43-sigvalue">
VpJzFiW62NK2ytlUkAYF....
</ds:SignatureValue>
....
</ds:Signature>
Is it possible to get ds:SignatureValue without the Id attribute?
It isn't possible to control the presence/value of that (and other) IDs, since it's hard-coded on the signer class. These IDs may be needed by some qualifying properties, hence being added.
I have n polygons with ids "test-1-1", "test-1-2" .... "test-1-n" which represent a single logical entity. Format of id can be generalized as < entity_name>-< entity_id>-< i>, where i is added to distinguish ids of multiple polygons.
My query here is, I want to display only "test" when any of these polygons is clicked. Currently id of selected polygon is displayed in info-box.
Is there any cesium way to do this? I would not prefer manipulating the strings at runtime.
A Cesium Entity has three fields of interest to the InfoBox (the thing that pops up when an Entity is selected).
entity.id - Each entity in a dataSource is required to have a unique id (a GUID will be auto-generated if no ID is supplied at creation). It is an arbitrary string and does not need to be human-friendly.
entity.name - This is the human-friendly name of the Entity. It does not need to be unique, you may have as many duplicate names as you like. It is half a line or less of plain text (not HTML).
entity.description - This is a sandboxed HTML description of the entity, and can span multiple paragraphs or include tables and other styling.
The InfoBox will attempt to show entity.name on its title bar by default, and will only fall back to show entity.id in the title bar if name is missing (because name is optional, id is not).
The body of the InfoBox only appears below the title bar if entity.description is set (otherwise only the bar is shown). The description is rendered with a sandboxed iframe (to offer some resistance to cross-site scripting for apps that display user-supplied entity descriptions).
I have n polygons with ids "test-1-1", "test-1-2" .... "test-1-n" ...
For this case, I would keep the existing ids, and set name to be the string you wish to see in the InfoBox popup. Multiple entities can have the same name but not the same id.
I ve got an Ontology written in OWL with Protege. But I don't find a solution for creating relations between Classes. Of course, there is a "subclass" relation, but I want to define my own relations. So I have a class hierarchy (which consists out of "subclass"-relations) but I want to create a relation, i.e. "has_Relation", to connect two classes.
My aim is to write a java programm in which I can get the information "which class is parentclass of a class?" and "to which class is a has_Relation connection?"
(I am not talking about individuals - I'm just talking about classes)
Thank you very much for your help in advance!
Best Regards
Natan
The simplest way to do this is to use an annotation property. In Protégé, select the class you want to relate to another class, then click the + beside "Annotations" in the Annotations tab. Then add the has_Relation property with the second button on the top left of the window. Then select the Entity IRI tab and the Classes subtab, select the other class you want to relate to and you're done.
However, you should rather not do this if has_Relation is an object property or a datatype property. If such is the case, you can use "punning", that is, you can make new individuals in the Individuals tab with the same names as the classes you want to relate. Then you relate them as if they were normal individuals. Note that this is allowed and valid in OWL 2 DL.
a bit late, but:
You can also go to the tabs menu and active the object properties tab
(Window> Tabs -> Object Properties )
Then you can create your own object property and assign its domain and range to which ever classes you want ( Description area of the individual property ).
I think the title should make it pretty clear. I was wondering how you can assign a class to an object on stage. As you would do with actionscript:
var objectname:ClassName = new ClassName();
This would make a new object, but the current object already exists, it just needs to be notified that it's of the type "ClassName" so it can inherit it's properties.
I've also tried assigning the "ClassName" in the linkage as either the base path or the class name. But in either situations I get an error saying that the class needs to be unique when I use the same class on multiple objects.
So I would need something like
//example exists on stage
example.class = ClassName
Thanks
I will answer your question with a question : why are you assigning the same class on multiple objects?
If what you want is a common behavior for those objects, you should create your class and assign it has the Base Class on those objects.
I don't think there's a way to do just do that. But I do suggest you look into the decorator design pattern The idea here is that you don't change the class, but you "decorate it" with more functions as needed.
Hope this helps !
You seem to have this the wrong way around. You define a class in order to set specific behavior & properties for an object. In a real life example, if I want to build a radio , I will come up with a radio design & implement it. Now if I need several radios, I will use the same implementation to manufacture them.
If I now wish to turn my radio into a TV , I can't just tell my radio, hey , you're a TV now. I can either decide beforehand that I want a radio/tv object and switch behavior whenever necessary or I can create a new TV object and add the radio functionality to it by adding a radio component to my TV object.
var radio:Radio // your current object
//example 1
radio.switchToTv();
//example 2
var radioTv:Tv = new Tv( radio );