Invalid foreign key relationship when I try to add a new custom object to an exsting lead

Question

I have a Lead and a custom object called Social Account (API Name = Social_Account__c).

I have set a relationship as follows: Lead is a parent of Social Accounts. so a lead has many social accounts.

In the Social Account, I made a custom field named Lead (Data Type: Lookup) to make the relationship.

and here is a lookup detail:

API Name: Lead__c

Related to Lead

Child Relationship Name: Social_Accounts

Related List Label: Social Accounts

I would like to add new social accounts to existing lead if there is a lead with the same email address.

---

Social_Account__c social_account = new Social_Account__c();
/*add whatever fields on social_account*/

List<Lead> leads =[select Id from Lead where Email =:emailAddress ];
if(leads.size()>0)
{ 
    Lead existing_lead = new Lead(Id = leads[0].id);
    //ideally i would like to do something like this
    social_account.Lead__c.id = existing_lead.id; //this is where I get an error from

    insert social_account;
    update existing_lead;
}

---

but i get a following error message:

Error: Compile Error: Invalid foreign key relationship: Social_Account_c.Lead_c

what am I doing wrong? I would appreciate any suggestions.

thanks

Answer 1

You can't "go through relation" with dot (.) operator with updates, just with reading data.

Change your social_account.Lead__c.id = existing_lead.Id; into social_account.Lead__c = existing_lead.Id;

Should be all that's needed. Salesforce relations can be

SET by directly modifying the field you have created: Social_Account__c.Lead__c, putting there Id of object you want to point to.

GET (explored) by modifying the field name a bit and using the dot, in your case it's probably Social_Account__c.Lead__r.(whatever fields on Lead you want).

The "_c" and "_r" are for custom objects, for standard ones for example there is Opportunity.AccountId field for setting but if you want to explore up to Account you type Opportunity.Account.Name.

---

If you'll have trouble remembering it - don't worry, me too ;) Usually when I get such compilation error I try it with query builder (in Apex Explorer or the Eclipse plugin). I click through hierarchy on the object, it's children, it's parents etc and usually can use pieces of generated query directly in my Apex code.