Mendix (Intermediate and Advanced) pt 3
Compilado de questões dos Learning Paths de nível intermediário e avançado.
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1
Which statement about log nodes is true?
Log nodes are defined in the Developer portal.
Log nodes are dynamically registered on application startup.
Mendix has a list of predefined log nodes. No other nodes can be defined.
Log nodes are added through the Set Log Level screen in Studio Pro.
2
Which of the following statements about log levels is true?
Messages at the Trace level need your immediate attention.
Messages at the Debug level signal a big problem with your application.
Messages at the Warning level need to be resolved immediately.
Messages at the Info level occur during normal operation of your app.
3
Who is responsible for writing the error messages that your application generates?
The developer.
The project manager.
Logs are generated automatically.
The user
4
Which description best describes a Stack Trace?
A list of functions that were being called when an error occurred.
A list of functions that might have the same problem as the error you’re experiencing.
A series of log messages at the log level Trace that are related.
A list of objects that were in memory at the time the error occurred.
5
Why should you use an enumeration for your log node names?
You should not, log node names should use a special entity to get their names.
You should not, constants are the preferred for log node names.
This allows you to standardize the log node name and group all log node names in your app.
Log events only accept enumerations as input for the log node names.
6
How do you ensure that your log node name is available after startup?
All log nodes in your app are added to the list automatically upon startup.
You can’t, you will have to wait until one of your log activities is reached before you can see the log event.
Add it to the list of log nodes in Studio Pro.
Add a log activity to a microflow that you call in the After Startup microflow.
7
You want to add a log event to an error flow on your REST Call to indicate a weather API call failed in your Holiday Request application. Which level of logging should you use?
Error, if the weather is unavailable you can still request vacation but someone should immediately investigate.
Critical, you’re unable to request vacation if you do not know the weather at your destination.
Info, this is part of the normal operation of your app, these things happen, nothing to see here.
Warning, you can still continue but someone should look into why the REST call is failing and whether further action is needed.
8
Where in Mendix Studio Pro can you configure XPaths?
List Views
Text widgets
Page access rules
Navigation
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Which Widget feature utilizes XPaths?
Selectable data constraints on Reference Selectors
The tab index of a Group Box
Styling properties of Action Buttons
Dynamic text in Labels
10
Where can you utilize XPaths in microflows?
In the input parameter
In the ‘Retrieve’ action
In the ‘Commit’ action
In the ‘Open page’ action
11
You can use XPath to:
Add data
Modify data
Compare data
Delete data
12
Which is NOT an XPath operator?
<>
or
<=
!=
13
What shortcut shows a list of available expressions in an Expression Editor?
Using Mendix Assist
Using the Expression wizard
Clicking the help button
Typing Ctrl + Space
14
Which activity would you use in a microflow to bring an object into the scope of a microflow?
Retrieve Object
Call Object
Select Object
Create Object
15
How do you begin typing an XPath?
<
[
.
(
16
If you want to open the XPath auto-complete menu, you need to press:
Ctrl + O
Shift+Space
Ctrl + Space
Ctrl + Shift
17
Say you are writing an XPath in a Retrieve action for the VacationRequest entity in a Microflow. If you write in the XPath window [Status = ‘Cancelled’], what will be returned?
A list of all requests except the ones that are cancelled.
A new list of requests where the Status will not be ‘Cancelled’.
A list of all requests with the status set to ‘Cancelled’.
A new object with Status = ‘Cancelled’.
18
Let’s assume you add a new decimal attribute to the VacationRequest entity called ‘DaysUsed’. The value represents the total amount of days used for the requested vacation. If you write a microflow with a Retrieve action, what will be the return if we use the following XPath [DaysUsed < 4.5 and not(VacationManagement.VacationRequest_Submitter/Administration.Account)]
A list of all VacationRequests that have been approved and are shorter than 4.5 days
A list of all VacationRequests that are shorter than 4.5 days and have a Submitter assigned
A list of all VacationRequests that are shorter than 4.5 days and do not have a Submitter assigned
A list of all VacationRequests that are longer than 4.5 days
19
Which of the following is NOT a benefit that XPath provides to the Mendix Platform?
XPath can be used to automatically generate pages and widgets to show data on.
The XPath notation can be derived visually by walking over the path between two entities in a domain model.
XPath provides a uniform query language regardless of which of the supported databases is used.
XPath abstracts away individual deviations from the SQL standard in the underlying supported databases.
20
What does the following XPath query return? //Product [OrderManagement.OrderLine_Product/OrderManagement.OrderLine /OrderManagement.OrderLine_Order != $Order]
All the products that aren’t ordered on the affected order.
All the products that aren’t ordered at any order.
All the products that are ordered at least once, including on the affected order.
All the products that are ordered at least once, but not on the affected order.
21
This XPath query can be optimized as follows: [OrderManagement.OrderLine_Product /OrderManagement.Product/MinimalStock > 50] [OrderManagement.OrderLine_Product /OrderManagement.Product/Status = 'Active']]
[OrderManagement.OrderLine_Product/OrderManagement.Product [MinimalStock > 50 and Status = 'Active'] ]
[OrderManagement.OrderLine_Product/OrderManagement.Product [MinimalStock > 50 or Status = 'Active'] ]
[OrderManagement.OrderLine_Product [OrderManagement.Product/MinimalStock > 50] [OrderManagement.Product/Status = 'Active'] ]
[OrderManagement.OrderLine_Product/OrderManagement.Product [MinimalStock > 50] or [Status = 'Active'] ]
22
The request as result of this XPath can be optimized as follows: [OrderManagement.Stock_Product /OrderManagement.Product/Status = 'Deactivated' or OrderManagement.Stock_Supplier /OrderManagement.Supplier/Active = false()]
The request cannot be optimized, since it is consuming two different paths.
[OrderManagement.Stock_Product/OrderManagement.Product [Status = 'Deactivated' or Active = false()] ]
The request is automatically optimized by the database server.
The request can be optimized by splitting it into different requests and joining the results.
23
Which of the following statements is NOT an XPath best practice with regards to optimal performance?
Limit the usage of the OR operator, as it can negatively impact performance.
Limit the number of associations that are crossed when defining a constraint.
When combining multiple constraints, start with the most constraining limit first.
Do not use XPath when you can use SQL instead.
24
Which operation can be used to select a specific set of rows in a table?
Set operation
Projection
Selection
Elimination
25
The Set Union operation combines two lists into one that contains:
all elements from both lists
all elements that appear in only one of the two lists
all elements that exist in both lists
one version of the objects from both lists
26
What operation combines the data from two different entities into one table?
Projection
Set union
Set difference
Cartesian product
27
What does the Projection operation do?
It allows you to add two lists into one.
It allows you to project an entity onto a data view.
It allows you to select attributes for all objects.
It allows you to select objects from an entity.
28
What can you use a constrain function for?
To use Java in your XPath queries.
To filter on strings and dates in XPath queries.
To call a microflow into your XPath.
To select objects based on enumerations.
29
Which of the queries below can be used to filter on dates two weekso in the past?
[%CurrentDay%] - 2 + [%WeekLength%]
[%BeginOfCurrentDay%] - 2 * [%WeekLength%]
[%BeginOfCurrentDay%] - 2 + [%WeekLength%]
[%CurrentDay%] - 2 * [%WeekLength%]
30
One of your XPath queries that use the contains() function is not performing very well. What is the most likely root cause?
You are using the function on a string that is set to 'unlimited'.
You have not implemented a separate XPath query for all the languages that your app is using.
You are using the function on an attribute that is not a string
You have implemented a custom function in JavaScript.
31
When using the and operator:
The 'and' operator is not available unless you have a boolean attribute in your entity.
The 'and' operator will give a different result based on how you write the XPath query.
You can use the 'and' operator everywhere in an XPath expression.
The 'and' operator needs to be followed by two brackets to work.
32
The not() function:
Generates the same query as the != operator.
Generates a slow query.
Cannot be used when you use the or the operator.
Can only be used on boolean attributes.
33
Which statement best describes how you would retrieve all related objects in the most optimal way?
Mendix will optimize your XPath expressions at runtime.
When you use an object in your XPath, you need to compare it to an entity directly like this: [Sales.Customer_Account/Administration.Account = $currentUser] to get the most optimal query.
You can only compare an object to the id attribute of an entity of the same type to get the most optimal query.
When comparing to a related entity, it is enough to stop at the association to get the most optimal query.
34
When should you apply an index?
You should apply indexes on attributes that are used in searches when the performance of your app is not up to par.
You should always apply indexes on all your attributes; that makes your app faster.
You should only apply indexes on boolean attributes.
Mendix will apply indexes where needed, you don’t need to worry about that.
35
What is normalization?
The act of removing unneeded entities from your domain model.
The addition of attributes to your entities to store data in multiple places to your app runs faster.
The addition of entities to your domain model that help you track normal behavior of your app.
The removal of duplicate data from your domain model.
36
Why would you want to do normalization?
To increase the performance of your XPath retrieves.
To prepare your app for deployment on a cloud node.
To make your domain model easier to read.
To remove duplicate data from your app so you can avoid insertion, update, and deletion anomalies.
37
What is denormalization?
The duplication of information in several entities to increase performance.
The addition of more entities in your domain model to increase performance.
The addition of more associations to your domain model to increase performance.
The removal of XPath expressions to increase performance.
