Salesforce DML and its methods

Delete_demo.apxc

Contact [] delContact = [SELECT Id FROM Contact where LastName = 'YLast'];
delete delContact;
System.debug(delContact);

dml_exception_demo.apxc

try {
    Account account  = new Account ();
    insert account;
} catch (DmlException e) {
    System.debug('Error occured' + e.getMessage ());
}

dml_methods.apxc

//List <Contact> dummyList = ;
Database.SaveResult [] allRes = Database.insert(new List<Contact> {
		new Contact (FirstName = 'Nony_0', LastName = 'Mang'),
        new Contact (FirstName = 'Nony_1', LastName = 'Mang'),
        new Contact (FirstName = 'Nony_2', LastName = 'Mang'),
        new Contact (FirstName = 'Nony_3', LastName = 'Mang'),
		new Contact ()
	}, false);
for (Database.SaveResult res : allRes) {
    if (res.isSuccess ()) {
       System.debug('inserted successfully : ' + res);
      	
    } else {
        for (Database.Error err : res.getErrors ()) {
        	System.debug('Error in inserting data : ' + err);    
        }
    }
}

Database.DeleteResult [] resDel = Database.delete([SELECT Id from CONTACT where FirstName 	LIKE 'Nony_%']);

for (Database.DeleteResult resD : resDel) {
    System.debug(resD);
}

insert_demo.apxc

List <Contact> ctList = new List<Contact> { new Contact (FirstName = 'Raki_jab',
                   LastName = 'KG',
                   Email = '[email protected]',
                                                         Department = 'Marketing',
                   Description = 'New Lead person'),
    
    				new Contact (FirstName = 'Nandi',
                   LastName = 'Jack',
                   Email = '[email protected]',
                                 Department = 'Technology',
                   Description = 'New Lead person'),
    
    				new Contact (FirstName = 'Mahi',
                   LastName = 'KG',
                   Email = '[email protected]',
                  	Department = 'Finance',
                   Description = 'New Lead person'),
    				
    				new Contact (FirstName = 'Jan',
                   LastName = 'KG',
                   Email = '[email protected]',
                   Department = 'Finance',
                   Description = 'New Lead person')
    
    };

//System.debug(ct);                                          
insert ctList;
System.debug(ctList);

List<Contact> listToUpdate = new List<Contact>();

for (Contact ct : ctList) {
    if (ct.Department == 'Finance') {
        ct.Title = 'Finance Analyst';
         listToUpdate.add(ct);
    }
    
    if (ct.Department == 'Marketing') {
        ct.Title = 'Marketing Analyst';
        listToUpdate.add (ct);
    }
}

update listToUpdate;
System.debug(listToUpdate);

upsert_demo.apxc

Contact contact_j = new Contact (FirstName = 'Josh_B', LastName = 'Kaplan', Email = '[email protected]');
insert contact_j;
System.debug (contact_j);

contact_j.Description = 'This is the joshs contact';

Contact contact_K = new Contact (FirstName = 'Ketti', LastName = 'Mairo', Email = '[email protected]');

List <Contact> upsertList = new List<Contact> {contact_j, contact_k};

upsert upsertList;

System.debug (upsertList);





/*
    Upsert with email external look up field
*/
Contact personX = new Contact (
	FirstName = 'PersonX',
    LastName = 'XLast',
    Email = '[email protected]',
    Description = 'Description for the personX'
);
insert personX;
System.debug (personX);

Contact personY = new Contact (FirstName = 'PersonX',
    LastName = 'YLast',
    Email = '[email protected]',
    Description = 'This is the updated description');
upsert personY Contact.fields.Email;
System.debug(personX);
System.debug(personY);

working_related_record.apxc

Account ac = new Account (Name='MondayMoningAccount');
insert ac;
Contact someCt = new Contact (
	FirstName = 'MoJack',
    LastName ='Jan',
    AccountID = ac.ID
);
insert someCt;


/*
    Updating
*/

Contact ctx = [SELECT Account.Name 
               from Contact WHERE FirstName = 'MoJack' 
               and
               LastName = 'Jan' LIMIT 1];

System.debug(ctx);
ctx.Phone = '(415)555-1213';
ctx.Account.Industry = 'Technology';

update ctx;
System.debug(ctx);

update ctx.Account;
System.debug(ctx.Account);