Trigger to update count of child records with custom field of parent object

Hey guys, today in this post we are going to learn about how to update count of child records with custom field value into parent object using trigger map list in Salesforce.
Real time scenarios:- Write a trigger on parent object where create a custom field as Employee (Number type).
If user insert the parent record, the child record should be automatic inserted equal to the same value of employee.
Or if user update the value of employee less then the total number of child records, in this case the child records should be exist only equal to employee size, rest records of child object should be automatic removed.
parentObjTrigger:- Custom Fields & Relationships
Create a custom field on parent Object name as Employee__c (Number Type).
childObjTrigger:- Custom Fields & Relationships
Create a lookup relationship field on child Object name as childLookup__c :: Lookup(parentObjTrigger).
Files we used in this post example:-
EmployeeSizeTrigger.apxt
Apex Class Trigger
It will be fired whenever insert or update a record on parent object
Parent Cusotm Object:- parentObjTrigger__c
Custom Field:- EmployeeName__c
Parent Object with Custom Field
Trigger on parent object and updae the count of related child records with thecustom field value of parent object.
Child Custom Object:- childObjTrigger__c
Custom Field:- childLookup__c : Lookup(parentObjTrigger)
Child Object with Custom Field
childLookup__c : Lookup(parentObjTrigger) field it is help to communicate on parent object.
Final Output

Other post that would you like to learn
Step 1:- Apex Class Trigger : EmployeeSizeTrigger.apxt
From Developer Console >> File >> New >> Apex Trigger
Originally published at https://www.w3web.net on August 12, 2020.