cascading | feature rich API

With -replace instead of .replace():

I'm not that familiar on how to do this in PHP, however you are looking for something that resembles "OnSelectedIndexChanged" function. On a quick search the Internet came back with selectedIndex and selectedProperies for PHP. I added the link below.

SelectedIndex Example

The UML literature frequently refers to part-whole relationships regarding aggregation/composition. However, the definitions in the UML standard have evolved (see UML 2.5.1):

Sometimes a Property is used to model circumstances in which one instance is used to group together a set of instances; this is called aggregation. (...)

• Shared: Indicates that the Property has shared aggregation semantics. Precise semantics of shared aggregation varies by application area and modeler.

• Composite: Indicates that the Property is aggregated compositely, i.e., the composite object has responsibility for the existence and storage of the composed objects.

Composite aggregation is a strong form of aggregation that requires a part object be included in at most one composite object at a time. If a composite object is deleted, all of its part instances that are objects are deleted with it.

In other words, there is no precise semantic specified for the "aggregation" (i.e. shared aggregation) that would make a difference from a simple association: shared aggregation is a modeling placebo.

The relationship between database constraints and UML modeling are therefore not as straightforward as you would assume.

Moreover, there is no general one-to-one mapping between a database schema and an UML model. More than one database schema could be used to implement the same UML class diagram. And conversely, more than one UML diagram may represent the design that is implemented by a given database schema. So the best we can do here, is to consider close-matches.

In your database, the table with the FOREIGN KEY constraint would correspond to a potential component in a composition, or an element of a shared aggregation, or an associated instance in a simple association :

• a ON DELETE CASCADE could help to implement a composite aggregation: it's the only way in SQL to implement the kind of lifecycle management that you would expect in a composition: the components would be deleted when the composite is. It could as well implement an ordinary association, if some business rules/contracts (e.g. UML post conditions) would require such a related deletion.

• a ON DELETE SET NULL could help to implement a shared aggregation, if its smeantics would be defined as you mean: if the aggregate is deleted, its elements would not be deleted, and could therefore be shared. But it could as well implement any ordinary association, since the deletion of an associated instance would not trigger a deletion either and the constraint would allow to maintain a clean referential integrity.

I've updated your code with the following changes:

• I added evt.preventDefault() just for this demonstration, so that clicking on the anchor does not navigate to a non-existent page. Remove this when you copy it back to your own code.
• I set prevSelected to the td element by assigning the evt Event's currentTarget property, which always refers to the element on which the event was bound (in this case, tab).
• I changed the CSS selector for your final rule from .td1.current, .td1 .anchor.current to .td1.current, .td1.current .anchor. This simplifies the JavaScript, as we only need to apply the current class to the tab/td element, not to both the td and the a. As you can see when you run the code, the text is highlighted appropriately.

I'm assuming that the pages linked to (e.g., Items/sheet002.htm) have their corresponding HTML updated to have the correct classes applied? If not you'll need to add some code to check the current URL against the href of the anchor and update the corresponding tab's classList to add the current class. Should be as simple as updating that final if to be something like:

To answer your question:

1. Yes, this is possible to achieve.

The thing that was missing here is that your useUser() is called inside StateProvider component, i.e. on the same level with the context provider, whereas for useContext() to work, it has to be called one level down the context provider (StateProvider as a wrapper). In this case, it would be your App component.

A working code would be as follow:

C++ Copy Constructors: must I spell out all member variables in the initializer list?

Yes, if you write a user defined copy constructor, then you must write an initialiser for every sub object - unless you wish to default initialise them, in which case you don't need any initialiser - or if you can use a default member initialiser.

the object contains some member variables which are pointers to its other member variables)

This is a design that should be avoided when possible. Not only does this force you to define custom copy and move assignment operators and constructors, but it is often unnecessarily inefficient.

But, in case that is necessary for some reason - or custom special member functions are needed for any other reason - you can achieve clean code by combining the normally copying parts into a separate dummy class. That way the the user defined constructor has only one sub object to initialise.

Like this:

You can create an object with all values you want to pass and use it like this

withRouter is a Higher Order Component, import it and decorate the ClusterServersDropdown component.

A few things need to be fixed;

1. You need to keep a state value for the selected server selectserver.