How Do I populate the Last Login Date from User object into a custom object/field? [duplicate]

Question

This question already has an answer here:

• Execute an action / run a trigger every time a User logs in to Salesforce 3 answers
• Extract logindate from user object and populate a new field in a custom object via batch apex 1 answer

Aim – Pull the last login date from the user object into my custom object and populate a particular field

Now I am under the impression that LastLoginDate on the user object is not accessible through formulas in custom objects. The only way that LastLoginDate is accessible is through triggers

**Custom Object** Object Name Mason_Object
API Name Mason_Object__c

**Field I would like to update is on the mason_object** Field Label : LastLogin Api Name : LastLogin__c Data type: Date/Time

I have written the following trigger (see below) however its not pulling through any values. Any ideas why ?

trigger lastloginDate on Mason_Object__c(before update) {

User u = [SELECT LastLoginDate FROM User WHERE Id =:UserInfo.getUserId()];
trigger.new[0].LastLogin__c = u.LastLoginDate;

}

Answer 1

trigger lastloginDate on Mason_Object__c(before update) {
User u = [SELECT LastLoginDate FROM User WHERE Id =:UserInfo.getUserId()];
for(Mason_Object__c c : Trigger.new){
//May want to put some condition checks
c.LastLogin__c = u.LastLoginDate;
}
}

But can't this be achieved by some cross object formulas, or are you not able to manipulate an active user? I don't know I've never done cross object formulas on Users

Update to your comments --

The only way I can think to do it then is so whenever User.oldMap != User.newMap(pseudo), make that kick off your Custom Object and Update it