List has no rows for assignment to SObject  error

 Consider following query:

   
      id p;

      user u = [SELECT Id from user where Name = :username];

      if (u != null)

      p = u.Id;

•  The above code will fail if there is no user record with the matching username. It doesn't actually return a null.

 It would be safer to do the following:

    id p;

     user[] userlist = [SELECT Id from user where Name = :username];

     if (userlist.size() > 0)

       p = userlist[0].Id;

Trigger for Adding and removing User to Permission set based on User roles

trigger AssignPermissionSet on User (after insert,after Update) {
    PermissionSet pereset = [SELECT Id FROM PermissionSet WHERE Label ='SBU Impact Visible'];
    Set<ID> addIds = new Set<Id>(),
            removeIds = new Set<Id>(),
            roleIds = new Map<Id, UserRole>([
        SELECT  Id FROM UserRole
        WHERE   Name LIKE '%E&C%' OR Name LIKE '%Commerical Ops%' OR Name LIKE '%Energy & Chemicals%' OR Name LIKE '%All Fluor%'
    ]).keySet();
    for(User record: Trigger.new) {
        (record.IsActive && roleIds.contains(record.UserRoleId)? addIds: removeIds).add(record.Id);
    }
   
    PermissionSetAssignment[] permissionSetList = new PermissionSetAssignment[0];
    addIds.removeAll(new Map<Id, AggregateResult>([SELECT AssigneeId Id FROM PermissionSetAssignment
       WHERE AssigneeId = :addIds AND PermissionSetId = :pereset.Id GROUP BY AssigneeId]).keySet());
   
    for(Id userId: addIds) {
        permissionSetList.add(new PermissionSetAssignment(PermissionSetId = pereset.id, AssigneeId = userId));
    }
    upsert permissionSetList;
    delete [SELECT Id FROM PermissionSetAssignment WHERE AssigneeId = :removeIds AND PermissionSetId = :pereset.Id];
}

                            PermissionSetAssignment:

• Use the PermissionSetAssignment object to query permission set assignments to find out which permission sets are assigned to which users.
• Each user may be assigned to many permission sets and each permission set may be assigned to many users.
• Each PermissionSetAssignment ID represents the association of a single user and single permission set.

For example, to search for all of the permission sets assigned to a particular user:

SELECT Id, PermissionSetId
FROM PermissionSetAssignment
WHERE AssigneeId = '005600000017cKt'

To search for all users assigned to a particular permission set:

SELECT Id, AssigneeId
FROM PermissionSetAssignment
WHERE PermissionSetId = '0PS30000000000e'

Note:

You can also create a new permission set assignment, or use delete to remove a permission set that's assigned to a user. To update an assignment, delete an existing assignment and insert a new one.

Possible Errors:

Solution:

When assigning a permission set, if the PermissionSet ​ has a UserLicenseId, its UserLicenseId and the Profile ​UserLicenseId must match.


If Permission set is already present for user.Following Error will occur.

   DML Statement in 'after trigger' and not in 'before trigger'?


According to document, first Before trigger fire and then after trigger fire.In between of these events all the records saved to database but doesn't committed yet

• Before insert event
• Data committed to database
• After insert event

Means when you use before insert operation records are not committed to database so If we change the trigger context record's value then we don't need perform DML (This is Id is not generated because it is not committed to database)

• Once it is committed to database means the record Id is generated and your trigger records in read only mode you can't update the values now(because it is committed to database).That's why we need to perform extra DML for updating records.

Note: If in after event if any error occurs then complete DML operation rollback.

Best way if you want to update the same record in trigger then always go with before event. This way you can skip the extra DML.

       System.ListException: Duplicate id in list: 001XXXXXXXXXXXX

Lists can hold duplicate values, but if it contains duplicate sobject IDs and you try to update you'll get the error.

Solution:

1. Create a map of  <id,sobject>
2. Convert the list to Map so that the duplicate IDs are removed.
3. Update the values part of the Map.

Sample code :

// pick up any id from your salesforce org, in this sample it is account id.
id aid = '0017F000002WkkdQAC';

list <account> al = new list <account>();

for(account a : [select id from account where id ='0017F000002WkkdQAC']){
account acc = new account(id = aid);
    al.add(a);
    al.add(acc);
}
//create a map that will hold the values of the list
map<id,account> accmap = new map<id,account>();

//put all the values from the list to map.
accmap.putall(al);
if(accmap.size()>0){
update accmap.values();
}

             Using JSON in Visualforce page in Salesforce

JSON stands for “Java Script Object Notation“.

JSON.serialize() is used to generate JSON. It is a lightweight data-interchange format.

JSON is built on two structures:

• A collection of name/value pairs. In various languages, this is realized as an object, record, struct, dictionary, hash table, keyed list, or associative array.
• An ordered list of values. In most languages, this is realized as an array, vector, list, or sequence.

---------------------------------------------------------------------------------------------------------

<apex:page controller="sample1" action="{!parseJson}">
    <p>
       <b> displaying json format in visulaforce page</b>
    </p>
    {!text1}
 
    <apex:pageblock >
         <p>
        <b> Displaying Json data in PageBloack Table</b>
    </p>
        <apex:pageblockTable value="{!jsonList}" var="json">
            <apex:column headerValue="id" value="{!json.id}"/>
            <apex:column headerValue="name" value="{!json.name}"/>
        </apex:pageblockTable>
    </apex:pageblock>
</apex:page>


-------------------------------------------------------------------------------------


public class sample1 {
 public String text1 {get;set;}
    public list<JsonWrapper> jsonList{get;set;}
    public sample1()
    {
         jsonList=new list<JsonWrapper>();
    } 
    public void parseJson()
    {
        String soql = 'SELECT Name FROM Account LIMIT 5';
        List<Account> acct = Database.Query(soql);
        text1 = JSON.serialize(acct);
        jsonList=(List<JsonWrapper>) System.JSON.deserialize(text1,List<JsonWrapper>.class);
    }
 
 
    public class JsonWrapper{
        public string id{get;set;}
        public string name{get;set;}
    }
}

Image:

Create a modal or popup box in salesforce Lightning

I am going to demonstrate salesforce lightning popup model. This model is very simple here I used aura: if condition to show and hide the model.

LightningPopup.cmp

<aura:component >

    <aura:attribute name="openmodel" type="boolean" default="false"/>

    <div class="slds-m-around--xx-large">

        <button class="slds-button slds-button--brand" onclick="{!c.openModel}">Pop up Model</button>  

        <aura:if isTrue="{!v.openmodel}">

            <div role="dialog" tabindex="-1" aria-labelledby="header99" class="slds-modal slds-fade-in-open ">

                <div class="slds-modal__container">

                    <div class="slds-modal__header">

                        <button class="slds-button slds-modal__close slds-button--icon-inverse" title="Close" onclick="{!c.closeModel}">

                            X

                            <span class="slds-assistive-text">Close</span>

                        </button>

                        <h2 id="header99" class="slds-text-heading--medium">Some Inspiration never dies</h2>

                    </div>

                    

                    <div class="slds-modal__content slds-p-around--medium">

                        <p><b>Stay true to yourself, yet always be open to learn. Work hard, and never give up on your dreams, even when nobody else believes they can come true but you. These are not cliches but real tools you need no matter what you do in life to stay focused on your path.

                            

                            </b>

                        </p>

                    </div>

                    

                    <div class="slds-modal__footer">

                        <button class="slds-button slds-button--neutral" onclick="{!c.closeModel}" >Cancel</button>

                        

                    </div>

                </div>

            </div>

            <div class="slds-backdrop slds-backdrop--open"></div>

            

        </aura:if>

    </div>

</aura:component>

---------------------------------------------------------------------------------------------

LightningPopup.controller

({

    openModel: function(component, event, helper) {

        

        component.set("v.openmodel", true);

    },

    

    closeModel: function(component, event, helper) {

        

        component.set("v.openmodel", false);

    }

})

------------------------------------------------------------------------------

Preview it using salesforce Lightning App:

<aura:application extends="force:slds">

    <c:LightningPopup />

</aura:application>