DML can be performed on a single record or to a batch or collection of records. Salesforce allows only 150 DML iteration per transaction, therefore it is advised that we should perform DML on a collection rather on a single record, it improves the overall execution efficiency of the code.<\/p>\n

Ex: inefficient code=><\/p>\n

For(account a: accountlist){<\/p>\n

If(a.name ==\u201dsomevalue\u201d){<\/p>\n

a.phone = \u201c9999999999\u201d;<\/p>\n

}<\/p>\n

Update a;<\/p>\n

}<\/p>\n

Ex: More Efficient code=><\/p>\n

List<Account> acctoUpdate = new list<Account>();<\/p>\n

For(account a: accountlist){<\/p>\n

If(a.name ==\u201dsomevalue\u201d){<\/p>\n

a.phone = \u201c9999999999\u201d;<\/p>\n

}<\/p>\n

acctoUpdate .add(a);<\/p>\n

}<\/p>\n

Update acctoUpdate;<\/p>\n

DML and Database Class methods<\/strong><\/p>\n

Apex has offered Data manipulation in two ways, DML operations or the use of Database class method.<\/p>\n

Ex: DML<\/p>\n

List<Account> accountList =\u00a0new\u00a0List<Account>();<\/p>\n

accountList.add( new Account(Name=\u201dTest1\u201d));<\/p>\n

accountList.add( new Account(Name=\u201dTest2\u201d));<\/p>\n

insert accountList;<\/p>\n

Database Class<\/p>\n

List<Account> accountList =\u00a0new\u00a0List<Account>();<\/p>\n

accountList.add( new Account(Name=\u201dTest1\u201d));<\/p>\n

accountList.add( new Account(Name=\u201dTest2\u201d));<\/p>\n

Database.SaveResult[] SaveResultList =\u00a0Database.insert(accountList,\u00a0false);<\/p>\n

If the parameter passed in the method is true, then it behaves exactly same as the DML insert operation.<\/p>\n

The main reason to use Database Class over the DML operation is the ability to partially process records if an error is encountered, in DML the whole transaction is roll backed in case of an exception.<\/p>\n

You can use DML if you want to through Apex Exception immediately interrupting the control flow.<\/p>\n