Salesforce interview with McKesson Corporation
1.In what ways we can achieve pagination?
We can add pagination to a page using a standard set controller by utilizing the next and previous actions. To control the number of records displayed on each page, use a controller extension to set the pageSize.This approach gets records from cache if records are already iterated.
We can use pagination by using limit in offset query. It can be used to do more customization
Pagination
By default variables do not store values. Once the new transaction happens earlier state i.e. transaction passed or failed is removed. Batch apex can implement Database.stateful which allow variables to store previous state.
Database.SaveResult[] srList = Database.insert(scope, false); After it, in finish() method we can collect and process information for failed and successful records. Scope is set of records in that transaction, false is allowing partial transaction.
After it, in finish() method you can collect and process information for failed and successful records.
If DML Operation is Success Will Get Record Id From Database By Using getId() Method in Database.SaveResult Class.
If any DML Operation Fails while Processing The Record no way to Get the Failure Record Id in Database.Error Class.
3.What is mixed DML operation and how to avoid it?
This error means that two Sobjects(setup & non-setup) that we are using in our
code can not mix during the same transactions. This restriction exists because
some sObjects affect the user’s access to records in the org.
For example, We cannot insert an account and then insert a user or a group
member in a single transaction.
To avoid this error, we should perform DML operation on standard/custom object
records in a different transaction.
Solution For Mixed DML Operartion.
1. Separate the Setup object and Non-Setup object dml operation using Future
Method.
2. System.RunAs : Enclose mixed DML operations within System.runAs blocks
to avoid the mixed DML error in test class.
4. What is the use of Test.Start, Test.Stop?
Test.startTest and Test.stopTest are used for asynchronous apex, like Batch Apex
and Future calls. Calling method(s) between Test.startTest and Test.stopTest
ensure that any asynchronous transactions finish executing before Test.stopTest() exits.
startTest()
Marks the point in our test code when our test actually begins. Use this method
when we are testing governor limits.
stopTest()
Marks the point in our test code when our test ends. Use this method in
conjunction with the startTest method.
5.Create field using apex? Is it possible?
We can create field using Metadata API.
11. Difference between Visualforce and Lightning?
12. Difference of using apex controller in lightning and Visualforce?
1. Methods in aura enabled are asynchronous. Methods in Visualforce Page is synchronous
2. All the required variables declared in controller use getter,setter to display values in Vf page.
Lightning have attribute which do not bind with controller variable directly.
3.When redirecting from one page to another then visualforce we use pageReference. It send request to controller and it will provide new page.
14.How is security enforced in lightning as compared to visualforce?
Shared Resources
In Visualforce, we build complete pages. In Lightning, the basic building blocks are components, which are reusable and easily replaceable. A .
In a Lightning application, components share key resources like the global window and JavaScript interpreter. We have to be careful about using functions that take control of the entire window, such as JavaScript alerts and global calls, or writing code that takes a great deal of JavaScript processing, as it will affect other components in the same window.
Data Security
Visualforce enforces the active user’s CRUD and FLS permissions when a page renders a Salesforce object. Lightning doesn’t do any client-side authorization, so it doesn’t respect these permissions.
LockerService isolates individual Lightning components in their own containers so they can’t interact with one another directly except through tools provided by the framework, like Aura attributes or events.
15.User dont have access to the fields and want to display in lightning? What need to be done?
16.Does OWD, profile, permission set which gets enforced when using with sharing ?
Only record level security is enforced with sharing. It does not take object level and field level security into consideration.
17.How to create test data for test classes? What are the ways we can get data?
18. We have three different objects. Delete records from all the three objects and they dont have any relation?
19. Write a batch to delete records for three unrelated object?
20. What is database.Stateful?
21. Can class extend interface?
Class cannot extend interface but implement it.Also, one class can extend only one class.
Reference
https://salesforce.stackexchange.com/questions/82969/count-of-records-processed-during-batch
https://developer.salesforce.com/forums/?id=9060G000000I5tPQAS
https://www.salesforcecodecrack.com/2018/08/how-to-get-failure-record-ids-from.html
https://blog.webnersolutions.com/create-salesforce-custom-object-using-apex-code
Tooling API to create fields
https://tecknikh.com/create-custom-field-using-tooling-api-in-apex/
1.In what ways we can achieve pagination?
We can add pagination to a page using a standard set controller by utilizing the next and previous actions. To control the number of records displayed on each page, use a controller extension to set the pageSize.This approach gets records from cache if records are already iterated.
We can use pagination by using limit in offset query. It can be used to do more customization
Pagination
<apex:page standardController="Account" extensions="accPagination" recordSetVar="accounts">
<apex:pageBlock title="Viewing Accounts">
<apex:form id="theForm">
<apex:pageBlockSection >
<apex:dataList var="acc" value="{!accounts}">
{!acc.Name}
</apex:dataList>
</apex:pageBlockSection>
<apex:panelGrid columns="4">
<apex:commandLink action="{!first}">FIRST</apex:commandLink>
<apex:commandLink action="{!next}">NEXT</apex:commandLink>
<apex:commandLink action="{!previous}">PREVIOUS</apex:commandLink>
<apex:commandLink action="{!last}">LAST</apex:commandLink>
</apex:panelGrid>
</apex:form>
</apex:pageBlock>
</apex:page>
AccPagination Controller: To display only 5 records per page use PageSize
public class accPagination{
public accPagination(ApexPages.StandardSetController controller) {
}
}
2. How to check how many records have passes or failed using batch apex? Get failure records ID in batch apex?By default variables do not store values. Once the new transaction happens earlier state i.e. transaction passed or failed is removed. Batch apex can implement Database.stateful which allow variables to store previous state.
Database.SaveResult[] srList = Database.insert(scope, false); After it, in finish() method we can collect and process information for failed and successful records. Scope is set of records in that transaction, false is allowing partial transaction.
After it, in finish() method you can collect and process information for failed and successful records.
If DML Operation is Success Will Get Record Id From Database By Using getId() Method in Database.SaveResult Class.
If any DML Operation Fails while Processing The Record no way to Get the Failure Record Id in Database.Error Class.
3.What is mixed DML operation and how to avoid it?
This error means that two Sobjects(setup & non-setup) that we are using in our
code can not mix during the same transactions. This restriction exists because
some sObjects affect the user’s access to records in the org.
For example, We cannot insert an account and then insert a user or a group
member in a single transaction.
To avoid this error, we should perform DML operation on standard/custom object
records in a different transaction.
Solution For Mixed DML Operartion.
1. Separate the Setup object and Non-Setup object dml operation using Future
Method.
2. System.RunAs : Enclose mixed DML operations within System.runAs blocks
to avoid the mixed DML error in test class.
4. What is the use of Test.Start, Test.Stop?
Test.startTest and Test.stopTest are used for asynchronous apex, like Batch Apex
and Future calls. Calling method(s) between Test.startTest and Test.stopTest
ensure that any asynchronous transactions finish executing before Test.stopTest() exits.
startTest()
Marks the point in our test code when our test actually begins. Use this method
when we are testing governor limits.
stopTest()
Marks the point in our test code when our test ends. Use this method in
conjunction with the startTest method.
5.Create field using apex? Is it possible?
We can create field using Metadata API.
MetadataService.CustomField customField = new MetadataService.CustomField();
customField.fullName = 'Test__c.TestField__c';
customField.label = 'Test Field';
customField.type_x = 'Text';
customField.length = 42;
MetadataService.AsyncResult[] results = service.create(new List<MetadataService.Metadata> { customField })
10. Use case of Visualforce page? 11. Difference between Visualforce and Lightning?
Visualforce components are page-centric and most of the work is done on the server. Lightning Components are client-side centric, which makes them more dynamic and mobile friendly.
1. Methods in aura enabled are asynchronous. Methods in Visualforce Page is synchronous
2. All the required variables declared in controller use getter,setter to display values in Vf page.
Lightning have attribute which do not bind with controller variable directly.
3.When redirecting from one page to another then visualforce we use pageReference. It send request to controller and it will provide new page.
14.How is security enforced in lightning as compared to visualforce?
Shared Resources
In Visualforce, we build complete pages. In Lightning, the basic building blocks are components, which are reusable and easily replaceable. A .
In a Lightning application, components share key resources like the global window and JavaScript interpreter. We have to be careful about using functions that take control of the entire window, such as JavaScript alerts and global calls, or writing code that takes a great deal of JavaScript processing, as it will affect other components in the same window.
Data Security
Visualforce enforces the active user’s CRUD and FLS permissions when a page renders a Salesforce object. Lightning doesn’t do any client-side authorization, so it doesn’t respect these permissions.
LockerService isolates individual Lightning components in their own containers so they can’t interact with one another directly except through tools provided by the framework, like Aura attributes or events.
15.User dont have access to the fields and want to display in lightning? What need to be done?
16.Does OWD, profile, permission set which gets enforced when using with sharing ?
Only record level security is enforced with sharing. It does not take object level and field level security into consideration.
17.How to create test data for test classes? What are the ways we can get data?
18. We have three different objects. Delete records from all the three objects and they dont have any relation?
19. Write a batch to delete records for three unrelated object?
20. What is database.Stateful?
Database.Stateful in the class can maintain state across the transactions. When using Database.Stateful, only instance member variables hold or retain their values between transactions. Static member variables do not hold their values & values are reset between transactions.
Maintaining state is useful for counting records as they’re processed. It can be used for Capturing the failed record information in Execute method between all transactions and assigning to member. And use that member in Finish method.
Example
We want to perform logic like aggregate totals of the opportunity amounts as they were processed. We can use this count and send mail in final method to the users with job processed count and failure batch job count.
If we don’t implement Database.Stateful, all static and instance member variables are reset that is set back to their original values.
21. Can class extend interface?
Class cannot extend interface but implement it.Also, one class can extend only one class.
https://salesforce.stackexchange.com/questions/82969/count-of-records-processed-during-batch
https://developer.salesforce.com/forums/?id=9060G000000I5tPQAS
https://www.salesforcecodecrack.com/2018/08/how-to-get-failure-record-ids-from.html
https://blog.webnersolutions.com/create-salesforce-custom-object-using-apex-code
Tooling API to create fields
https://tecknikh.com/create-custom-field-using-tooling-api-in-apex/