How to add a new lead and update an existing lead in Salesforce

Question

I am new to Apex development and I'm starting to work on my project in Apex. I would like to do following:

---

using an email service //I figured this part
get emailAddress from an email //know how to do this
if there is already exisiting lead or contact with the same emailAddress
update his information
else
create new lead

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I would like to kow how I can search my database (saleforce's leads and contacts) and update existing user's info.

Answer 1

In the Salesforce built-in help you can find some info about the InboundEmail object. The page contains also 2 examples about working with Contacts and Leads based on email address extracted from the message.

Answer 2

You should execute a query on lead and contact using the email address as the criteria for you query. If it returns 0 records for the Lead and 0 records for the Contact, then you would create a new Lead.

Your query could return more than 1 record for either Lead or Contact, so you will have to develop a strategy to handle that case. Email address is not required to be unique.

public class StackOverflowExample {

public static void test(String email) {
    handleNewEmail(email);
}

private static void handleNewEmail(String email) {
    List<Lead> leads = [select id, email from Lead where email = :email];
    List<Contact> contacts = [select id, email from Contact where email = :email];
    if (leads.size() == 0 && contacts.size() == 0) {
        //Create new lead
        insert new Lead(Company = 'Lead Company', FirstName = 'firstname', LastName = 'lastname', Email = email);
    } else if (leads.size() == 1) {
        // Update this lead
        leads[0].FirstName = 'newfirstname';
        update leads;
    } else if (contacts.size() == 1) {
        // Update this contact
        contacts[0].FirstName = 'newfirstname';
        update contacts;
    } else {
        // Must be more than 1 contact or lead
        System.debug('\nMore than 1 contact or lead.');
    }
}

}

The other option is to execute a search limiting the scope to email fields.

public class StackOverflowExample {

public static void test(String email) {
    handleNewEmail(email);
}

private static void handleNewEmail(String email) {
    List<List<SObject>> searchResults = [FIND :email IN Email Fields RETURNING 
                Lead(Id, FirstName, LastName), 
                Contact(Id, FirstName, LastName)];
    List<Lead> leads = ((List<Lead>)searchResults[0]);
    List<Contact> contacts = ((List<Contact>)searchResults[1]);
    if (leads.size() == 0 && contacts.size() == 0) {
        //Create new lead
        insert new Lead(Company = 'Lead Company', FirstName = 'firstname', LastName = 'lastname', Email = email);
    } else if (leads.size() == 1) {
        // Update this lead
        leads[0].FirstName = 'newfirstname';
        update leads;
    } else if (contacts.size() == 1) {
        // Update this contact
        contacts[0].FirstName = 'newfirstname';
        update contacts;
    } else {
        // Must be more than 1 contact or lead
        System.debug('\nMore than 1 contact or lead.');
    }
}

}