Mendix advanced certificate 157
Questions and Correct Answers
What is a Persistable entity? -
✅An Entity that can be saved in the database.
What is a Non-Persistable entity? -
✅An entity that can only be saved in runtime memory.
What is a Generalized entity? -
✅An entity that lends its attributes, associations, event handlers, validation rules
and any other properties to another entity.
What is a Specialized entity? -
✅An entity that inherits all or part of its attributes, associations, event handlers,
validation rules and any other properties from another entity.
what are the system member properties? -
✅CreatedDate, ChangedDate, Owner, ChangedBy
How do you show multiple specialized entities in the same list view? -
✅By adding a template for every specialized entity while using the default for the
generalized entity.
What do you need to do after an Object type decision? -
✅Cast to entity to the correct specialization.
What should you do if the Object type decision is empty? -
✅Create a log message, since this is unexpected behavior.
Why should you use inheritence? -
✅It allows you to make reusable microflow, which increases the consistency and
maintainability of your app.
when should you use a 1-1 association over inheritance? -
✅when the entity in question isn't a true specialization of the generalized entity
and/or the generalized entity's properties are not required when dealing with the
entity in question.
Why is creating a new entity and making it a specialization of the FileDocument or
Image entity preferred over using original entities? -
✅The original entities are part of the System module, which makes them ineditable.
What indicates ownership over an association. -
✅A dot on that entity's side of the association.
Why is the main downside of a *-* association -
, ✅It uses a lot more memory that other associations.
What is an index? -
✅An extra table for a given entity in the database with ID's and a specified
attribute(s) in a sorted order which allows for faster queries.
When do you use an index? -
✅On entities with a lot of objects that are read more than written and on the most
searched attributes, that also have many possibilities.
What is the downside of an index? -
✅every time an object is added, the entire index table needs to be updated, which
can potentially cause performance issues.
What are the 4 stages of a domain model restructering? -
✅1. extend your domain model
2. model the data conversion
3. deploy the new model and convert the data.
4. clean up the model.
What does the expression [reversed ()] do? -
✅it tells mendix to reverse the direction in which a association is read.
What does localization on a datetime attribute do? -
✅It changes the datetime value to the time zone of the user when used or viewed.
The value is still stored on UTC time.
When should you turn localization off? -
✅when time offset is irrelevant
What is the Mendix Client? -
✅The Client runs in your browser and renders the front-end of your application. it
makes use of HTML, CSS and JavaScript. It talks with Mendix Runtime and stores
local objects within a session.
What is mendix runtime? -
✅This is the application server that provides the Runtime environment of your apps
and executes any logic defined in the application model. it talks with both the mendix
client and the database server.
What is the Database server? -
✅Any form of database that is supported by mendix. stores all data from your app
and is structured based on the domain models. it talks with mendix runtime.
what type of resource are pages, stylesheets and images in mendix? -
✅Static resources
Why would you choose database over Xpath as a data source for a list view? -
✅Constrains are easier to specify and are less resource intensive, furthermore they
can be used by offline mobile apps.
Questions and Correct Answers
What is a Persistable entity? -
✅An Entity that can be saved in the database.
What is a Non-Persistable entity? -
✅An entity that can only be saved in runtime memory.
What is a Generalized entity? -
✅An entity that lends its attributes, associations, event handlers, validation rules
and any other properties to another entity.
What is a Specialized entity? -
✅An entity that inherits all or part of its attributes, associations, event handlers,
validation rules and any other properties from another entity.
what are the system member properties? -
✅CreatedDate, ChangedDate, Owner, ChangedBy
How do you show multiple specialized entities in the same list view? -
✅By adding a template for every specialized entity while using the default for the
generalized entity.
What do you need to do after an Object type decision? -
✅Cast to entity to the correct specialization.
What should you do if the Object type decision is empty? -
✅Create a log message, since this is unexpected behavior.
Why should you use inheritence? -
✅It allows you to make reusable microflow, which increases the consistency and
maintainability of your app.
when should you use a 1-1 association over inheritance? -
✅when the entity in question isn't a true specialization of the generalized entity
and/or the generalized entity's properties are not required when dealing with the
entity in question.
Why is creating a new entity and making it a specialization of the FileDocument or
Image entity preferred over using original entities? -
✅The original entities are part of the System module, which makes them ineditable.
What indicates ownership over an association. -
✅A dot on that entity's side of the association.
Why is the main downside of a *-* association -
, ✅It uses a lot more memory that other associations.
What is an index? -
✅An extra table for a given entity in the database with ID's and a specified
attribute(s) in a sorted order which allows for faster queries.
When do you use an index? -
✅On entities with a lot of objects that are read more than written and on the most
searched attributes, that also have many possibilities.
What is the downside of an index? -
✅every time an object is added, the entire index table needs to be updated, which
can potentially cause performance issues.
What are the 4 stages of a domain model restructering? -
✅1. extend your domain model
2. model the data conversion
3. deploy the new model and convert the data.
4. clean up the model.
What does the expression [reversed ()] do? -
✅it tells mendix to reverse the direction in which a association is read.
What does localization on a datetime attribute do? -
✅It changes the datetime value to the time zone of the user when used or viewed.
The value is still stored on UTC time.
When should you turn localization off? -
✅when time offset is irrelevant
What is the Mendix Client? -
✅The Client runs in your browser and renders the front-end of your application. it
makes use of HTML, CSS and JavaScript. It talks with Mendix Runtime and stores
local objects within a session.
What is mendix runtime? -
✅This is the application server that provides the Runtime environment of your apps
and executes any logic defined in the application model. it talks with both the mendix
client and the database server.
What is the Database server? -
✅Any form of database that is supported by mendix. stores all data from your app
and is structured based on the domain models. it talks with mendix runtime.
what type of resource are pages, stylesheets and images in mendix? -
✅Static resources
Why would you choose database over Xpath as a data source for a list view? -
✅Constrains are easier to specify and are less resource intensive, furthermore they
can be used by offline mobile apps.
