Apex - Database Methods

Database class methods is another way of working with DML statements which are more flexible than DML Statements like insert, update, etc.

Differences between Database Methods and DML Statements

Insert Operation

Inserting new records via database methods is also quite simple and flexible. Let us consider the previous scenario wherein, we have inserted new records using the DML statements. We will be inserting the same using Database methods.

// Insert Operation Using Database methods
// Insert Customer Records First using simple DML Statement. This Customer Record will be
// used when we will create Invoice Records
APEX_Customer__c objCust = new APEX_Customer__C();
objCust.Name = 'Test';
insert objCust; // Inserting the Customer Records

// Insert Operation Using Database methods
APEX_Invoice__c objNewInvoice = new APEX_Invoice__c();
List InvoiceListToInsert = new List();
objNewInvoice.APEX_Status__c = 'Pending';
objNewInvoice.APEX_Customer__c = objCust.id;
objNewInvoice.APEX_Amount_Paid__c = 1000;
InvoiceListToInsert.add(objNewInvoice);
Database.SaveResult[] srList = Database.insert(InvoiceListToInsert, false);

// Database method to insert the records in List
// Iterate through each returned result by the method

for (Database.SaveResult sr : srList) {
if (sr.isSuccess()) {
// This condition will be executed for successful records and will fetch the ids
// of successful records
System.debug('Successfully inserted Invoice. Invoice ID: ' + sr.getId());
// Get the invoice id of inserted Account
} else {
// This condition will be executed for failed records
for(Database.Error objErr : sr.getErrors()) {
System.debug('The following error has occurred.');

// Printing error message in Debug log
System.debug(objErr.getStatusCode() + ': ' + objErr.getMessage());
System.debug('Invoice oject field which are affected by the error:'
+ objErr.getFields());
}
}
}

Update Operation

Let us now consider our business case example using the database methods. Suppose we need to update the status field of Invoice object but at the same time, we also require information like status of records, failed record ids, success count, etc. This is not possible by using DML Statements, hence we must use Database methods to get the status of our operation.

We will be updating the Invoice's 'Status' field if it is in status 'Pending' and date of creation is today.

The code given below will help in updating the Invoice records using the Database.update method. Also, create an Invoice record before executing this code.

// Code to update the records using the Database methods
List invoiceList = [SELECT id, Name, APEX_Status__c,
createdDate FROM APEX_Invoice__c WHERE createdDate = today];

// fetch the invoice created today
List updatedInvoiceList = new List();
for (APEX_Invoice__c objInvoice: invoiceList) {
if (objInvoice.APEX_Status__c == 'Pending') {
objInvoice.APEX_Status__c = 'Paid';
updatedInvoiceList.add(objInvoice); //Adding records to the list
}
}

Database.SaveResult[] srList = Database.update(updatedInvoiceList, false);
// Database method to update the records in List

// Iterate through each returned result by the method
for (Database.SaveResult sr : srList) {
if (sr.isSuccess()) {
// This condition will be executed for successful records and will fetch
// the ids of successful records
System.debug('Successfully updated Invoice. Invoice ID is : ' + sr.getId());
} else {
// This condition will be executed for failed records
for(Database.Error objErr : sr.getErrors()) {
System.debug('The following error has occurred.');

// Printing error message in Debug log
System.debug(objErr.getStatusCode() + ': ' + objErr.getMessage());
System.debug('Invoice oject field which are affected by the error:'
+ objErr.getFields());
}
}
}

We will be looking at only the Insert and Update operations in this tutorial. The other operations are quite similar to these operations and what we did in the last chapter.