Salesforce Apex Class update custom object lookup field with id from parent

Question

I am new to Apex and I’m struggling with creating a class to help me with some data analysis. I have data from a 3rd party (transactions__C) that has a field (fin_acct_txt__c) that is the pointer to another object (fin_accounts__C). I want to updated transactions__c with the id from fin_accounts__C into the lookup field transactions__c.fin_acct__c. I want to do this in a class versus a trigger as there would be thousands of records loaded from the 3rd party on a monthly basis. I think doing this in bulk would be more efficient. My thought is I create a list for transactions__c and a map for fin_accounts__c. Using the fin_acct_txt__c=fin_accounts__c.name I would be able to get the fin_accounts__c.id and update the transactions__c.fin_acct__c with that data. But being new to Apex seems to be causing me some problems that I’m unsure how to resolve. Here’s a copy of what I’ve done to date:

public class updateTxnFinAcctID {

// Build map of financial accts since that is unique

map<string ,fin_acct__c> finAccts = new map<string, fin_acct__c>
    ([select id,name from fin_acct__c where name!=null]);

//Iterate through the map to find the id to update the transactions
{
for(fin_acct__c finAcct: finAccts.values())
{
    if (finAcct.name != Null)
    {
        finAccts.put(finAcct.name, finAcct);
    }

// Find all records in transaction__c where fin_acct__c is null 
//and the pointer is the name in the map

list<Transaction__c> txns =[
    select id,fin_acct_txt__c from Transaction__c where fin_acct__c = null
    and fin_acct_txt__c=:finaccts[0].name];

//create the list that will be used to update the transaction__c

list <Transaction__c> txnUpdate = new list <Transaction__c>();
{
//Find the id from fin_acct__c where name = fin_acct_txt__c
for (Transaction__c txn: txns){
    finacct[0].Id =txn.fin_acct__c;
    txnUpdate.add(txn);
}
//3. Update transaction with ID

}
}
   // if (txnUpdate.size()>0 { update txnUpdate};
    system.debug(txnUpdate.size());
}
}

I seem to be in a doom loop. The error I get is “Expression must be a list type: Map” pointing to the list txns = [ …]. But as that is not unique, it must be list. But I would believe I’ve got something structurally wrong here and that is a symptom of a larger issue.

Thanks.

Gleb Gleb · Accepted Answer · 2016-08-23T08:06:40

I tried to understand what should to do your code, and I have a few tips, possibly they help to solve your issue:

1) In first loop over values of map finAccts you really don't need validation with if (finAcct.name != Null), because you already add it in SOQL query (where name!=null).

2) It's a bad practice - to put as a key to map different entities (for example, Ids and Names). I mean that when you queried fin_acct__c into the map finAccts, keys of the map are Ids of fin_acct__c. And then in the first loop you put in the same map the same objects only using their names as a key. If you really need such map with names as a keys is better to create new map and put the data there.

3) You execute SOQL query to Transaction__c object into the loop. It is likely to be the cause of an exception related to the SF limits (Especially if you are sure that the code will handle large amounts of data). Better collect all fin_acct__c names in list and move SOQL query out from the loop, using IN instead of = in where condition.

If I understood correctly that fin_acct_txt__c field contains names, not Ids, your class should looks something like:

public class updateTxnFinAcctID {
    Map<String ,fin_acct__c> finAccts = new Map<String, fin_acct__c>
        ([select id,name from fin_acct__c where Name != null]);

    Map<String, fin_acct__c> finAcctByNames = new Map<String, fin_acct__c>();
    for(fin_acct__c finAcct: finAccts.values()){
        finAcctByNames.put(finAcct.Name, finAcct);
    }

    List<Transaction__c> txns =[select id, fin_acct_txt__c, fin_acct__c
            from Transaction__c where fin_acct__c = null
            and fin_acct_txt__c IN finAcctByNames.keySet()];

    List <Transaction__c> txnUpdate = new List<Transaction__c>();
    for (Transaction__c txn: txns){
        fin_acct__c relatedFinAcct = finAcctByNames.get(txn.fin_acct_txt__c);
        if(relatedFinAcct != null){
            txn.fin_acct__c = relatedFinAcct.Id;
            txnUpdate.add(txn);
        }       
    }   

    if(!txnUpdate.isEmpty()){ 
        update txnUpdate;
        system.debug(txnUpdate.size());
    }
}

It possibly can contains some spelling mistakes, but it's a common idea.

Salesforce Apex Class update custom object lookup field with id from parent

1 Answers