Update | APEX DML Standalone Statements

Apex Update DML Statement 

To update an existing record, you need to use the update statement.

Example 1:

public static void main() {
    Account a = [SELECT Name from Account WHERE Name like‘ Sh % ’LIMIT 1]
    a.name = ‘Cyntexa’;
    update a;
}

Example 2:

 List < Contact > conList = [SELECT firstname, lastname FROM Contact WHERE
    createdDate = Today
];
Integer i = 1;
for (Contact cc: conList) {
    cc.firstname = cc.firstname + i);
i++;
}
update conList;

Note:

We cannot modify a list or collection in a for-each loop where its even elements are iterated. (infinite loop)