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D365 FO Technical Interview Questions

 

What are OOPS concepts?

The main concepts of OOPS used in D365 FO are:

  • Class and Objects
  • Data Abstraction: Showing only the essential information and hiding background details.
  • Encapsulation: Wrapping of data member and method to a single unit.
  • Inheritance Flowing of property of the parent class to the child class.
  • Polymorphism is the property of repeatedly using the same method to perform different things.

 

Interfaces & Abstract Class

The class implementing is the interface that implements all interface methods and there will not be any abstract Class requirement. There are many access modifiers available like abstract, protected, virtual, internal, public, and many more that are useful in the abstract Classes. Abstract classes will be very fast when compared to interfaces.

 

 

Interfaces

Abstract Class

The interface is the signature for a particular method.

Abstract class contains both the incomplete and complete methods.

Interface cannot be an implemented method

The abstract class is the implemented method.

The interfaces do not contain constructors, fields, or destructors but they have only the property’s signature with no implementation.

The abstract class contains constructors, fields, or destructors for implementing the properties.

The interface supports multiple inheritances.

The abstract class does not support multiple inheritances.

The class can also inherit more than one interface.

The class can inherit only one abstract

What are EDT and Base Enum?

EDT or Extended Data Type and Base Enumerations (Enums) are data types. They are created and managed in the development environment. Extended data types can be primitive data types like integers, strings, real numbers, and booleans. EDT extends the original properties of the data type that they inherit. In addition, some extra properties are added.

Base enums are a fixed set of values. Those values in the database are saved as integers but they have also a name (as referenced from X++ code) and a label (visible to users). You can have up to 255 values for Base enums. The integers in the database will take on the values 0 through 254.

The AOT in D365FO apps contains many existing EDTs and base enums that can be extended for use in your project, or you can create new data types

 

 

 

Difference between Clustered and Non-clustered index

 

 

An index is a disk-based structure linked to a table or view that facilitates quicker row retrieval. A table or view’s table or view’s columns are used to create keys in an index. 

 

 

Clustered Index 

A clustered index is created only when both the following conditions are satisfied – 

1.      The data or file, that you are moving into secondary memory should be in sequential or sorted order.

2.      There should be a key value, meaning it can not have repeated values. 

Whenever you apply clustered indexing in a table, it will perform sorting in that table only. You can create only one clustered index in a table like a primary key. A clustered index is as same as a dictionary where the data is arranged in alphabetical order. 

 

Non-Clustered Index

 

The non-clustered Index is similar to the index of a book. The index of a book consists of a chapter name and page number, if you want to read any topic or chapter then you can directly go to that page by using the index of that book. No need to go through each and every page of a book. 

The data is stored in one place, and the index is stored in another place. Since the data and non-clustered index are stored separately, then you can have multiple non-clustered indexes in a table. 

In a non-clustered index, the index contains the pointer to data. 

 

Difference between Clustered and Non-Clustered index 

CLUSTERED INDEX

NON-CLUSTERED INDEX

A clustered index is faster.

A non-clustered index is slower.

The clustered index requires less memory for operations.

A non-clustered index requires more memory for operations.

In a clustered index, the clustered index is the main data.

In the Non-Clustered index, the index is the copy of data.

A table can have only one clustered index.

A table can have multiple non-clustered indexes.

The clustered index has the inherent ability to store data on the disk.

A non-clustered index does not have the inherent ability to store data on the disk.

Clustered index store pointers to block not data.

Non-Clustered index storescontainThe non-clustered both value and a pointer to the actual row that holds data.

In a Clustered index leaf nodes are actual data itself.

In a Non-Clustered index leaf nodes are not the actual data itself rather they only contain included columns.

In a Clustered index, the Clustered key defines the order of data within a table.

In a Non-Clustered index, the index key defines the order of data within the index.

A Clustered index is a type of index in which table records are physically reordered to match the index.

A Non-Clustered index is a special type of index in which the logical order of the index does not match the physical stored order of the rows on the disk.

The size of The primary clustered index is large.

The size of the non-clustered index is compared relatively composite is smaller.

Primary Keys of the table by default are clustered indexes.

The composite key when used with unique constraints of the table acts as the non-clustered index.

 

 

 

What are Delete Actions in D365 FO

Delete Actions and OnDelete property indicate how deletions in the main table are handled in the related tables or child tables.

There are 3 types of options available.

Cascade,

 Restricted

Cascade + Restricted.

 

Cascade:

 

 If you have one parent table ParentTable and you have one child or related table ChildTable. If you are going to use CASCADE delete action or On delete property then on deletion of records in TABLE ParentTable, related records in TABLE ChildTable will also get deleted.

 

Restricted :

 

If you have one parent table ParentTable and you have one child or related table ChildTable. If you are going to use a RESTRICTED delete action or On delete property then on the deletion of a record in TABLE ParentTable, the system will not validate records in related Table ChildTable. If a related record exists in Table ChildTable then the system will not allow you to delete the record in Table ParentTable and throw an error.

 

CASCADE RESTRICTED

 

 if we have 3 tables i.e. parent table warehouse& related tables supermarket & stores. Table store is a child or related table of Table Supermarket and similarly, Table Supermarket is a child or related table of parent Table Warehouse. If we set the delete action CASCADE in between Parent Table warehouse and Related Table supermarket and again if we set the delete action CASCADE RESTRICTED in between Table supermarket and Related Table stores. Then on the deletion of the record in the Parent TABLE warehouse, the system will also delete all the related records of the TABLE supermarket & stores. But if you try to delete records in the supermarket and related records exist in Table stores then the system will not allow to delete records.

 

         What are Table Relations in D365?

A table relation associates two tables that contain related information. Usually, the primary key field of one table appears as a foreign key field of the related table. The table with the primary key is called the parent table. The table with the foreign key is called the child table.

In Microsoft Dynamics 365 there are :

  • Normal Relation
  • Field Fixed Relation
  • Related Field Fixed Relation
  • Foreign Key Relation

A normal relation is used to specify a relation without any conditions. A normal relation specifies related fields in another table. Multiple fields can also be added in normal relations. 

Condition is,  Table1.Field = Table2.Field

A Field Fixed Relation is used to specify relation fields to restrict the records in the primary table. Only records that meet the condition are selected. The field fixed is normally an enum.

The condition is ANDed with your relation here Table.Field = <EnumValue>

A Related Field Fixed Relation is used to specify relation fields to restrict the records in the related table. Only records that meet the condition are selected. The Related field fixed is normally an enum.

The condition is ANDed with your relation here, <EnumValue> = Table.Field

A Foreign Key Relation is used to specify a correspondence between a foreign key field in the present table to the primary key field in another parent table.

 

What are the different types of Menu Items available in D365?

There are three types of menu items in D365 FO:

Display Menu Item: Use this type when the menu item opens a form.

Output Menu Item: Use this type when the menu item will opening an SSRS report.

Action Menu Item: Use this type when the menu item will run a batch job. Or some other process, such as run by a class.

 

What is the chain of command?

 

Chain of Command is the term that describes how we customize or extend, base Microsoft code in Microsoft Dynamics 365. Microsoft's base objects and code cannot be changed directly in D365.

The name of the new class you create must end with the text ‘_Extension’. In the example above, the base Microsoft class was named ‘Class’. The name of the class we created was ‘Class_Extension’.

 

There are several different objects in Microsoft Dynamics 365 that can use a Chain Of Command. I will list the most common here.

Classes              

  [ExtensionOf(classStr(<NameOfBaseObject>))]

Tables              

 [ExtensionOf(tableStr(<NameOfBaseObject>))]

Forms              

 [ExtensionOf(FormStr(<NameOfBaseObject>))]

Datasource on a form.

[ExtensionOf(formDataSourceStr(SalesTable, SalesLine))]

Data field on a form

[ExtensionOf(formDataFieldStr(<NameOfBaseForm>,<NameOfDataSource>,<NameOfField>))]

Control of a form

 [ExtensionOf(formControlStr(<NameOfBaseForm>,<NameOfControl>))]

Data entities

 [ExtensionOf(tableStr(<NameOfBaseDataEntity>))]

 

 

 Explain the difference between extensions and overlays in Dynamics 365 customization.

In Dynamics 365, customizations are achieved through extensions and overlays.

Extensions add or modify functionality without changing original code, aiding in updates and maintenance.

Overlays involve modifying original code, which can complicate updates and maintenance.


 What are some common performance optimization techniques in Dynamics 365?

Performance optimization in Dynamics 365 involves:

  • Database Optimization: Use indexing, query optimization, and regular maintenance.
  • Code Optimization: Write efficient X++ code, minimize nested loops, and use caching.
  • System Configuration: Ensure adequate resources and optimize settings.
  • Batch Processing: Schedule jobs during off-peak hours and distribute them.
  • Data Management: Archive and purge old data, and consider data partitioning.
  • Monitoring and Diagnostics: Use tools to monitor performance and review metrics.


What are delegates in X++, and how are they used? Provide an example.

Delegates in X++ define a method signature for event handlers. They are declared with the 

delegate
 keyword and can invoke subscribed methods.

Example:

Here, MyDelegate is declared in  MyClass, and RaiseDelegate calls subscribed methods. EventHandlerClass contains the handler method.

class MyClass
{
    delegate void MyDelegate(int _value);

    public void RaiseDelegate(int _value)
    {
        this.MyDelegate(_value);
    }
}

class EventHandlerClass
{
    public static void MyEventHandler(int _value)
    {
        info(strFmt("Event handler called with value: %1", _value));
    }
}

MyClass myClass = new MyClass();
myClass.MyDelegate += EventHandlerClass::MyEventHandler;
myClass.RaiseDelegate(10);

class MyClass
{
delegate void MyDelegate(int _value);
public void RaiseDelegate(int _value)
{
this.MyDelegate(_value);
}
}
class EventHandlerClass
{
public static void MyEventHandler(int _value)
{
info(strFmt("Event handler called with value: %1", _value));
}
}
MyClass myClass = new MyClass();
myClass.MyDelegate += EventHandlerClass::MyEventHandler;
myClass.RaiseDelegate(10);


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