Relationship Query in Apex – Salesforce

Relationship Query in Apex – Salesforce

Relationship Query in Apex – Salesforce

Most of the times, we have relationships between the objects(master-detail OR lookup) and often we need to fetch the list of all child records related to parent record in SOQL. This can be achieved using relationship query in Salesforce.

We can also say it as a Inner Query (query inside query).

For using relationship query, most important is, to know the Name of relationship between the two objects. You can get this relationship name by going to the Look-up OR Master-detail field on child object. Here is the screen that you will see after clicking on the look-up/Master-detail field name that is present on child object.

Here are two examples.

1.First one is for Account(Parent) – Contact (Child) relationship. Below screen, we have opened the Lookup field present on contact(child object).

Child Relationship name2. The second one is for some custom object. When we create a custom relationship field on any object, we get an option to choose the name of relationship, while creating the look-up or Master-Detail relationship field. Below you can see the same, and then the same name is used in relationship queries.

How to create relationship name

Then this relationship name reflects on the custom field as shown below:

Child Relationship name - 2


So, in case of relationship between standard objects, relationship name is fixed already, and you can not change, but in case you are creating the relationship on your own, then you get the option of choosing the relationship name.

Now you have got the relationship name. We’ll see, how to construct the query required for our problem i.e. to get all the child records related to one parent record in a single query.

Here is a significant difference while making relationship queries for standard relationships(already defined by salesforce) and custom relationships(defined by user – b/w two custom objects OR b/w custom & standard object).

For example, for account and contacts relationship(already defined by salesforce), the query will be like:

List<Account> accList = [select id,name,(select name, id, email from contacts) from account];

Here you can see in the phrase (select name, id, email from contacts ), we have used the relationship name as it is mentioned on the field detail page as shown below:

Child Relationship name

But in case of custom relationship the query will be like:

List<Account> accList = [select id, (select id, name from tests__r) from account];

Here we have used __r with the relationship name. We have to use __r suffix after the relationship name shown on the field detail page as shown below:

Child Relationship name - 2

This relationship query returns all the accounts with all the child test records associated to each account record. You can use the query result as shown below:

//Perform the query on Account.

List<Account> accList = [select id, (select id, name from tests__r) from account];

//Iterate over the account with.
for(Account a : accList){

//For each account object, get the child records using tests__r and iterate over each child records.
for(test__c test : a.tests__r){

System.debug('The test name is:::::' +;



Limitation of Relationship Query:

  • In each specified relationship, only one level of parent-to-child relationship can be specified in a query. For example, if the FROM clause specified Account, the SELECT clause could only specify the Contact or other objects at that level. It could not specify a child object of Contact.
  • No more than 20 relationships can be specified in a single query.
  • In each specified relationship, no more than five levels can be specified in a child-to-parent relationship. For example, Contact.Account.Owner.FirstName (three levels).

Good Luck !! 🙂


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Transient Keyword – View State – Visualforce – Salesforce

Transient Keyword – View State – Visualforce – Salesforce

Transient Keyword – View State – Visualforce – Salesforce: We can use transient keyword with apex class’s instance variables when we want that values of those variables should not be transferred as part of the view state of visualforce page. This helps us reducing the view state of visualforce page. As we all know that, there is a limit of 135KB of view state and many times this “Transient” keyword helps us to reduce the view state.

There are certain points that we should consider while using the transient keyword:

  1. The value of transient variable is only transferred from controller to visualforce page but not as part of view state. As the value is not part of view state, the changed value of that variable is not transferred back from visualforce page to controller when a new request is made by clicking a button or link.
  2. We should use the transient keyword mostly in case where we have read only Visualforce page and data doesn’t need to be sent back to controller in further requests. A common use case for the transient keyword is a field on a Visualforce page that is needed only for the duration of a page request, but should not be part of the page’s view state and would use too many system resources to be recomputed many times during a request.

Here is a very common and excellent example to help understand the concept of transient variable:

Visualforce page:

<apex:page controller="ExampleController">
Time1: {!t1} <br/><br/>
Time-Transient: {!t2} <br/><br/>
<apex:form >
<apex:commandLink value="Refresh"/>

Below is the controller for the same, where we have transient variable declared:

public class ExampleController {

DateTime t1;
transient DateTime t2; //declare

public String getT1() {
if (t1 == null)
 t1 =;

return '' + t1;

public String getT2() {
if (t2 == null)
 t2 =;

return '' + t2;

Click for Demo

In the above example and demo, you can see that clicking the refresh button on the page causes the transient date T2 to be updated every time, because it is being recreated each time the page is refreshed. The non-transient date continues to have its original value, which has been de-serialized from the view state, so it remains the same.

Going into more details, we can understand it like, when user made first request that means; when this page was accessed first time, at that time both the values were null, and getter method of both the variables checked for null and assigned the value of “” to the variables and values got displayed on visualforce page. But When visualforce was displayed for the first time, in the view state, there was only the value of non-transient variable which is T1 and not the transient one T2.

So, when user clicks on refresh, a new request is made. The getter methods again tries to check for null. Because the view state has the value of non-transient variable available, the value is taken from view state and as it is not null, system does not refresh the value with latest “” value.

BUT, for transient variable, since the view state does not hold the previous value, the getter method could not find any value and considering it null again, the getter method assigns the latest value of “” to the variable. That is why the value of transient variable gets refreshed.

Understanding the above example can give you a fair idea of where and why to use the transient keyword.

So, if you want the value of your variable on visualforce page only once, don’t need the value in further requests to controller, then use transient keyword, to make your page lighter with less size of view state.

Good Luck !! 🙂

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Test class in salesforce with example

Test class in Salesforce with example

Test class in salesforce

Testing is an important part of SDLC. So, before deploying our code to production environment, Salesforce requires at least 75% of your code to be covered by our test classes whic. Salesforce has done that to make sure that our code doesn’t break in any situation in Production. Today we’ll see how we write the test class with example in Salesforce.

Some points regarding the test classes in Salesforce, which you have to know for sure:

  1. At least 75% of your Apex code must be covered by unit tests, and all of those tests must complete successfully. But this should not be our focus. We should aim for 100% code coverage, which ensures that you cover each positive and negative use case of your code to cover and test each and every branch of your code.
  2. Calls to System.debug are not counted as part of Apex code coverage.
  3. Test methods and test classes are not counted as part of Apex code limit. So, no worries about writing long test class with more methods just to make sure that all your code branches are covered.
  4. Every trigger you are trying to deploy should have at least 1% coverage, but yes overall coverage of your production org after getting your code deployed should be 75%, otherwise Salesforce won’t let you deploy your code.
  5. Class can be deployed on 0% coverage as well, but as I told in last point, that overall coverage of your production org after getting your code deployed should be 75%, otherwise Salesforce won’t let you deploy your code.

In the example below, we will learn how to write a very simple test class:

Apex Trigger:

trigger HelloWorldTrigger on Book__c (before insert) {
  Book__c[] books =;

Trigger Helper Class:

public class MyHelloWorld {
 public static void applyDiscount(Book__c[] books) {
   for (Book__c b :books){
     b.Price__c *= 0.9;

Test Class Code:

private class HelloWorldTestClass {
 static testMethod void validateHelloWorld() {
 Book__c b = new Book__c(Name='Behind the Cloud', Price__c=100);
 System.debug('Price before inserting new book: ' + b.Price__c);

 // Insert book
 insert b;


 // Retrieve the new book
 b = [SELECT Price__c FROM Book__c WHERE Id =:b.Id];
 System.debug('Price after trigger fired: ' + b.Price__c);

 // Test that the trigger correctly updated the price
 System.assertEquals(90, b.Price__c);

The key points while writing a test class are:

  1. You have to start your class with @isTest annotation, then only Salesforce will consider this class as test class.
  2. Keep your class as Private, and the best practice is to name your test class as your original Class or trigger Name + ‘Test’.
  3. Methods of your test class have to be static, void and testMethod keyword has to be used.
  4. Prepare your test data which needs to be existing before your actual test runs. There are multiple techniques of creating test data now a days, for example, setup method, static resources etc. For more details about @testsetup method check below link @testSetup method in apex test class
  5. Use Test.startTest() and Test.stopTest() to make sure that the actual testing of your code happens with the fresh set of governer limits. These methods help you to reset your governor limits just before your actual code of testing get executed.
  6. Once your test code runs between Test.startTest() and Test.stopTest(), you must use assert statements to test whether your actual code is executing correctly and giving the results as expected. In our case, we are test whether book’s price has been set to 90 or not. If this assert statement returns false, then your test class will fail, and will let you know, that something is not correct in your code, and you need to fix your original code.
  7. Because we are testing a simple trigger, we could not show the testing using negative use cases, but in an ideal world, you should write multiple methods in your test class, few should test your positive use cases, and other should test your negative test cases.

Test class trailhead

Create test class

Good luck with your test classes!! 🙂

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SObject row was retrieved via SOQL without querying the requested field

SObject row was retrieved via SOQL without querying the requested field

SObject row was retrieved via SOQL without querying the requested field is very common error in apex. As name of error suggest, this error occurs when we try to use some field of an object instance which is not queried.

There can be two possible reason for this error.

  1. When we try to use a field in Apex or visualforce which is not queried. For example:

    List accList = [SELECT Id, Name FROM Account WHERE Name like ='%test'];
    for(Account acc : accList){
    System.debug('Account industry is'+ acc.Industry);

    Or if we try to use it in visualforce page like this

    <apex:outputField value="{!acc.Industry}"/>

Solution for this type of problem is very easy we can simply add Industry field in SOQL query like this:

List accList = [SELECT Id, Name FROM Account WHERE Name like =’%test’];

But sometime our visualforce page or apex class is very complex and we don’t know which field will be used.  In SOQL there is no standard way of querying all fields of object. In that case we can query all fields from SOQL using dynamic query.  For details refer to below link:

Dynamic SOQL query to fetch all fields in Salesforce

2.  The error “SObject row was retrieved via SOQL without querying the requested field” can occur when accessing a Visualforce page with a standard controller and a custom controller extension.

When a standard controller queries an object for a Visualforce page, it only retrieves the fields from the object that are referenced in the page.
This improves efficiency by not retrieving fields that are not needed by the Visualforce page.

When a custom controller references a field that is not included in the page, the field data is not available, and the error occurs.


  • You can add a SOQL query to the custom controller that queries the missing fields
  • You can add a hidden reference to the field in the Visualforce page.
For example:
<apex:outputText value="{!Condition__c.Criterion__c}" rendered="false"/>

Official Salesforce link

Happy Coding 🙂


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Pagination using standard set controller salesforce

Pagination using standard set controller salesforce

We can use Standard set controllers provided by salesforce to implement pagination in visualforce. It is very easy to implement pagination using standard set controller. We can easily navigate through pages, move directly to first, last page or to next or previous pages using standard set controller. We can also decide how many records should be displayed in every page. We need to instantiate the StandardSetController and use the standard methods provided by salesforce to leverage the pagination functionality.

In example below we are displaying all opportunities in visualforce page with pagination. We have specified default page size 10.

Click for Demo

Pagination using standard set controller salesforce

Visualforce Page:

<apex:page controller="OpportunitiesPaginationController" tabStyle="Opportunity">
    <apex:form >
        <apex:actionFunction name="refreshPageSize" action="{!refreshPageSize}" status="fetchStatus" reRender="pbId"/>
        <apex:pageBlock id="pbId">
            <apex:pageBlockSection title="All Opportunities" collapsible="false" columns="1">
                <apex:pageBlockTable value="{!Opportunities}" var="oppObj">
                    <apex:column headerValue="Opportunity Name">
                        <apex:outputField value="{!oppObj.Name}"/>
                    <apex:column headerValue="Account Name">
                        <apex:outputField value="{!}"/>
                    <apex:column headerValue="Amount">
                        <apex:outputField value="{!oppObj.Amount}"/>
                    <apex:column headerValue="Stage">
                        <apex:outputField value="{!oppObj.StageName}"/>
                    <apex:column headerValue="Last Activity Date">
                        <apex:outputField value="{!oppObj.LastModifiedDate}"/>
                    <apex:column headerValue="Close Date">
                        <apex:outputField value="{!oppObj.CloseDate}"/>
                <apex:panelGrid columns="8"> 
                <apex:selectList value="{!size}" multiselect="false" size="1" onchange="refreshPageSize();">
                    <apex:selectOptions value="{!paginationSizeOptions}"/>
                <apex:commandButton status="fetchStatus" reRender="pbId" value="First" action="{!setCon.first}" disabled="{!!setCon.hasPrevious}" title="First Page"/> 
                <apex:commandButton status="fetchStatus" reRender="pbId" value="Previous" action="{!setCon.previous}" disabled="{!!setCon.hasPrevious}" title="Previous Page"/> 
                <apex:commandButton status="fetchStatus" reRender="pbId" value="Next" action="{!}" disabled="{!!setCon.hasNext}" title="Next Page"/> 
                <apex:commandButton status="fetchStatus" reRender="pbId" value="Last" action="{!setCon.last}" disabled="{!!setCon.hasNext}" title="Last Page"/> 
                <apex:outputText >{!(setCon.pageNumber * size)+1-size}-{!IF((setCon.pageNumber * size)>noOfRecords, noOfRecords,
                     (setCon.pageNumber * size))} of {!noOfRecords}
                <apex:outputPanel >                      
                    <apex:actionStatus id="fetchStatus" >
                        <apex:facet name="start" >
                          <img src="/img/loading.gif" />                    

Apex Code:

public class OpportunitiesPaginationController{
    Public Integer size{get;set;} 
    Public Integer noOfRecords{get; set;} 
    public List<SelectOption> paginationSizeOptions{get;set;}
    public OpportunitiesPaginationController(){
        paginationSizeOptions = new List<SelectOption>();
        paginationSizeOptions.add(new SelectOption('5','5'));
        paginationSizeOptions.add(new SelectOption('10','10'));
        paginationSizeOptions.add(new SelectOption('20','20'));
        paginationSizeOptions.add(new SelectOption('50','50'));
        paginationSizeOptions.add(new SelectOption('100','100'));
    public ApexPages.StandardSetController setCon {
        get {
            if(setCon == null) {                
                setCon = new ApexPages.StandardSetController(Database.getQueryLocator(
                      [select id,Name,AccountId,,Amount,StageName,CloseDate,LastModifiedDate from Opportunity]));
                noOfRecords = setCon.getResultSize();
            return setCon;
    //Changes the size of pagination
    public PageReference refreshPageSize() {
         return null;

    // Initialize setCon and return a list of record    
    public List<Opportunity> getOpportunities() {
         return (List<Opportunity>) setCon.getRecords();

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Avoid recursive trigger in salesforce

Avoid recursive trigger in salesforce using static variable

Avoid recursive trigger in salesforce using static variable

Recursion occurs when same code is executed again and again. It can lead to infinite loop and which can result to governor limit sometime. Sometime it can also result in unexpected output.

It is very common to have recursion in trigger which can result to unexpected output or some error. So we should write code in such a way that it does not result to recursion. But sometime we are left with no choice.

For example, we may come across a situation where in a trigger we update a field which in result invoke a workflow. Workflow contains one field update on same object. So trigger will be executed two times. It can lead us to unexpected output.

Another example is our trigger fires on after update and it updates some related object and there is one more trigger on related object which updates child object. So it can result too infinite loop.

To avoid these kind of situation we can use public class static variable.

In RecursiveTriggerHandler class, we have a static variable which is set to true by default.

Continue reading

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get current record id salesforce

get current record id salesforce

apexpages.currentpage().getparameters().get(‘id’) can be used to get current record id or other url parameters in apex code.

Many times we have requirement to get current record id or url parameters of visualforce page in apex code.

Many times we require the current record id in controller. For example we are redirecting from one visualforce page to another visualforce page using apex code and we have also set some parameters for second visualforce page. Then, in that case we can use apexpages.currentpage().getparameters().get(‘id’) to get parameter with id name or any other name.

One more example if we have a button on detail page overridden by visualforce page and once the button is pressed you require the id(or the other field values of that record) of the record from whose detail page the button was clicked. For this requirement also we can use ApexPages.CurrentPage().getparameters().get(‘id’) to get other parameters.

In the following example we will use a custom extension to get current record id and one parameter with name nameParam. Then we are using one visualforce page to display current record id and all fields related to that record id by querying using SOQL query and also displaying value of one more parameter with name nameParam. In this way we can get value of any parameter in Apex code.

Click for Demo

get current record id salesforce

Visualforce Page:

<apex:page standardController="Account" extensions="CurrentRecordIdDemoController">
  <apex:form >
    <apex:pageBlock >
        <apex:pageBlockSection title="Current account record Id is : {!currentRecordId}" collapsible="false">
            <apex:outputField value="{!}"/>
            <apex:outputField value="{!acc.AccountNumber}"/>
            <apex:outputField value="{!acc.Type}"/>
            <apex:outputField value="{!acc.Industry}"/>
        <apex:pageBlockSection title="Testing parameter" collapsible="false">
            Name is <b>{!parameterValue}</b>

Apex Code:

public class CurrentRecordIdDemoController{
public String currentRecordId {get;set;}
public String parameterValue {get;set;}
public Account acc{get;set;}

    public CurrentRecordIdDemoController(ApexPages.StandardController controller) {
        currentRecordId  = ApexPages.CurrentPage().getparameters().get('id');
        acc = [select id ,name, AccountNumber, Type, Industry from Account where id =: currentRecordId ];
        parameterValue = ApexPages.CurrentPage().getparameters().get('nameParam');

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actionstatus visualforce disable screen

actionstatus visualforce disable screen

actionStatus visualforce component displays the status of an AJAX update request. An AJAX request can either be in progress or complete.

Depending upon the AJAX request status (whether AJAX request is in progress or complete), this component will display different message to user. In many scenarios AJAX request takes some time. So we should display some message to user that your request is in progress. Once request is complete, we can display some different message to user.

Using actionstatus, we can also display some gif (graphic Interchange Format), which shows to user that their request is in progress. It gives very good presentation to end user.

In the example below, we are using actionStatus for commandbutton. We are showing account edit page to user. When user will click on save buttton, request will go to controller method. We are showing gif image to user while AJAX request is in progress using actionstatus component. We are using apex:facet tag inside actionstatus to show image and we have specified name value as ‘start’ in apex:facet tag. So It will show image when request is in progress. We can also use ‘stop’ value in name attribute of apex:facet to specify message when request completes.

Click for Demo

actionstatus visualforce disable screen

Visualforce Page:

<apex:page controller="actionStatusImage" tabStyle="Account">
    <apex:outputpanel >
        <apex:actionstatus id="actStatusId">
            <apex:facet name="start">
                <div class="waitingSearchDiv" id="el_loading" style="background-color: #DCD6D6;
                       height: 100%;opacity:0.65;width:100%;"> 
                    <div class="waitingHolder" style="top: 74.2px; width: 91px;">
                        <img class="waitingImage" src="/img/loading.gif" title="Please Wait..." />
                        <span class="waitingDescription">Saving...</span>
    <apex:form id="formId">
    <apex:pageBlock id="pgBlckId" title="New Account">
        <apex:pageBlockButtons >
            <apex:commandButton action="{!save}" value="Save" reRender="pgBlckId" status="actStatusId"/>
        <apex:pageBlockSection id="pgBlckSecId" title="Account Information" collapsible="false">
            <apex:inputField value="{!}"/>
            <apex:inputField value="{!account.Phone}"/>
            <apex:inputField value="{!account.Type}"/>
            <apex:inputField value="{!account.Rating}"/>
            <apex:inputField value="{!account.Industry}"/>
            <apex:inputField value="{!}"/>

Apex Code:

public class actionStatusImage {
    public Account account{get;set;}
    public actionStatusImage(){
        account = new Account();
    public Pagereference save(){
        //upsert account;
        return null;

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custom label in apex code salesforce

custom label in apex code salesforce example

We can use System.Label.labelName to access custom label in apex code.

Custom labels are custom text values that can be accessed from Apex classes or Visualforce pages. The values can be translated into any language Salesforce supports. Custom labels enable developers to create multilingual applications by automatically presenting information (for example, help text or error messages) in a user’s native language.
You can create up to 5,000 custom labels for your organization, and they can be up to 1,000 characters in length.

To access custom labels, Go To Setup — Create — Custom Labels. Click on New Custom Labels.Enter value for name, value and description. We can use custom label name to access custom label value in apex code using System.Label.labelName

New Custom Label

Advantage of using custom label is that label will be displayed to user depending on their language automatically. We need to specify translation for label using translation workbench.

After creating custom label we can use following code to use custom label in apex code.

Visualforce Page:

<apex:page controller="CustomLabelApexDemoController">
   <apex:form >
     <apex:pageblock >
       Value stored in custom label is: <b>{!customLabelValue}</b>
public class CustomLabelApexDemoController {
    public string customLabelValue{get;set;}
    public CustomLabelApexDemoController(){
        customLabelValue = System.Label.DemoLabel;

If custom label is part of managed package, then we also need to use namespace for accessing custom label in our custom apex code which is not part of managed package. Lets say DemoLabel is part of managed package and managed package namespace is ‘myName’. Then we need to use following code to access DemoLabel in apex code.

String customLabelValue = System.Label.myName.DemoLabel;

We can also use custom label in visualforce page. For more details check this post.

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