Because Apex is a data-focused language and is saved on the Force.com platform, it has direct access to your data in Salesforce. Unlike other programming languages that require additional setup to connect to data sources, with Apex DML, managing records is made easy! By calling DML statements, you can quickly perform operations on your Salesforce records.
This example adds the Acme account to Salesforce. An account sObject is created first and then passed as an argument to the insert statement, which persists the record in Salesforce.
`// Create the account sObject
Account acct = new Account(Name=**'Acme'**, Phone=**'(415)555-1212'**, NumberOfEmployees=100);
// Insert the account by using DML
insert acct;`
The following DML statements are available.
insert update upsert delete undelete merge
Each DML statement accepts either a single sObject or a list (or array) of sObjects. Operating on a list of sObjects is a more efficient way for processing records.
All those statements, except a couple, are familiar database operations. The upsert and merge statements are particular to Salesforce and can be quite handy.
The upsert DML operation creates new records and updates sObject records within a single statement, using a specified field to determine the presence of existing objects, or the ID field if no field is specified.
The merge statement merges up to three records of the same sObject type into one of the records, deleting the others, and re-parenting any related records.
When inserting records, the system assigns an ID for each record. In addition to persisting the ID value in the database, the ID value is also autopopulated on the sObject variable that you used as an argument in the DML call.
This example shows how to get the ID on the sObject that corresponds to the inserted account.
`// Create the account sObject
Account acct = new Account(Name=**'Acme'**, Phone=**'(415)555-1212'**, NumberOfEmployees=100);
// Insert the account by using DML
insert acct;
// Get the new ID on the inserted sObject argument
ID acctID = acct.Id;
// Display this ID in the debug log
System.**debug**(**'ID = '** + acctID);
// Debug log result (the ID will be different in your case)
// DEBUG|ID = 001D000000JmKkeIAF`
If you have a list containing a mix of new and existing records, you can process insertions and updates to all records in the list by using the upsert statement. Upsert helps avoid the creation of duplicate records and can save you time as you don’t have to determine which records exist first.
The upsert statement matches the sObjects with existing records by comparing values of one field. If you don’t specify a field when calling this statement, the upsert statement uses the sObject’s ID to match the sObject with existing records in Salesforce. Alternatively, you can specify a field to use for matching. For custom objects, specify a custom field marked as external ID. For standard objects, you can specify any field that has the idLookup property set to true. For example, the Email field of Contact or User has the idLookup property set. To check a field’s property, see the Object Reference for Salesforce and Force.com.
Upsert Syntax