Apex 開発：deepCloneとCloneの区別

普通の方(clone)

``` Account a = new Account(Name='Acme', BillingCity='New York');

Account b = new Account();
Account[] q1 = new Account[]{a,b};

Account[] q2 = q1.clone();
q1[0].BillingCity = 'San Francisco';

System.debug(q1[0].BillingCity); // San Francisco
System.debug(q2[0].BillingCity); // San Francisco

同じポインターのため、q1修正すると、q2の値も変更されるとのことです。

<h2>deepCloneの方</h2>

Account a = new Account(Name='Acme', BillingCity='New York');

Account b = new Account();
Account[] q1 = new Account[]{a,b};

Account[] q2 = q1.deepClone();
q1[0].BillingCity = 'San Francisco';

System.debug(q1[0].BillingCity); // San Francisco
System.debug(q2[0].BillingCity); // New York

List accts = [SELECT CreatedById, CreatedDate, LastModifiedById,
LastModifiedDate, BillingCity
FROM Account
WHERE Name='Acme' OR Name='Salesforce'];

// Clone list while preserving timestamp and user ID fields.
Account[] q3 = accts.clone();

// Verify timestamp fields are preserved for the first list element.

System.debug(q3[0].Id);
System.debug(q3[0].CreatedById);
System.debug(q3[0].CreatedDate);
System.debug(q3[0].LastModifiedById);
System.debug(q3[0].LastModifiedDate);

![image.png](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/550974/95b6f8fa-6f4a-4d38-f64b-c4f73c841697.png)

List accts = [SELECT CreatedById, CreatedDate, LastModifiedById,
LastModifiedDate, BillingCity
FROM Account
WHERE Name='Acme' OR Name='Salesforce'];

// Clone list while preserving timestamp and user ID fields.
Account[] q3 = accts.deepClone(false,false,false);

// Verify timestamp fields are preserved for the first list element.

System.debug(q3[0].Id);
System.debug(q3[0].CreatedById);
System.debug(q3[0].CreatedDate);
System.debug(q3[0].LastModifiedById);
System.debug(q3[0].LastModifiedDate);

![image.png](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/550974/e1babc7e-1406-cfbc-a364-4e4d5027b946.png)

「Id」、参照のみ「タイムスタンプ」と「自動採番」はこまめに扱いできる。
 ディフォルト：false