Anonymous Execution: System.LimitException: Too Many DML Statements: 151

Question

I am trying to run the following piece of code to update all Accounts without a primary contact. This method will look through all contacts of an account and assign the first contact it reads to be the primary contact of the account.

I am running into a System.LimitException: Too Many DML Statements: 151 error for exceeding 151 DML operations. Does anybody have any suggestions as to how I can resolve this?

public class setPrimaryContact {

public static void setPrimary(){

    boolean assigned = false;

    List<Account> accountList = [
        SELECT Name, Primary_Contact__c, (select id, Lastname, Type__C from contacts)
        FROM Account
    ];

    //Loop through all accounts
    for(Account acc:accountList){
        assigned = false;
        //Check if the account has contacts
        if(acc.Contacts.size()>0){
            //Check if the account already has a primary contact
            if(acc.Primary_Contact__c == null){
            //Loop through each contact
                for(Contact c:acc.Contacts){
                    //Check to see if the contact is a primary contact
                    if(!assigned && (c.Type__c == 'Primary Contact')){
                        //Assign that primary contact to be the Primary_Contact__c of the account
                        acc.Primary_Contact__c = c.Id;
                        assigned = true;
                        update acc;
                    }
                }
            } else {
                System.debug(acc.Name+' already has a primary contact .');
            }

            if(!assigned){
                System.debug(acc.Name+' has no primary contacts.');
            }
        } else {
            System.debug(acc.Name+' has no contacts.');
        } 
    }
}

}

Answer 1

You have DML (database operations) inside a loop. That pattern is not going to work on the Salesforce platform.

What you must do: create and initialize a List variable i.e. List<Account> myListToUpdate = new List<Account>(); before you enter your outermost Account loop. Once you do your magic and set your fields, add each Account record that is to be updated to your List. Do NOT perform DML inside your loops. Remove the update acc; line from your code altogether, and replace it with myListToUpdate.add(acc);

Once you exit all of your loops, update your List variable.

Finally... here is some simple documentation to get you started learning to "think bulkified". https://trailhead.salesforce.com/en/content/learn/modules/apex_database/apex_database_dml