Lock record on field update

I need a way to lock an Idea and its comments from being editable. I have a time-based workflow already set up to change a custom field after 30 days. The custom field is called voting status with options of "Open" and "Locked". I'm thinking of two options:

Create a trigger to lock the record down after the field change similar to how it locks after an approval process is locked.

Or create a trigger that makes the record read-only after the field change.

Any ideas or examples on how to achieve this? I've been searching the API documentation and found the FOR UPDATE statement, but I haven't been able to implement anything.

Example so far:

Trigger IdeaRecordLock on Idea (after update, after insert) { for (Idea a : Trigger.New) { if (a.Voting_Status__c == 'Locked') { List lockemSockem = [SELECT Id FROM Idea WHERE Voting_Status__c = 'Locked' FOR UPDATE]; } } }

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Once the Opportunity goes to Closed Won or Closed Lost, use a workflow rule to change the record type to, say, 'Closed'. Then, use a different page layout for the 'Closed' recordtype wherein all the fields are read only on layout 'Closed'

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 lock the whole record for everyone except System Admins once the level is "Archived" or "Closed". Putting a prior value around your level field will thus not help you, since it is only checking if that specific field has changed.

I would suggest you implement something like this:

1. Create a new checkbox "Record Locked".
2. Create a workflow that sets the checkbox to true once the level is "Archived" or "Closed". Optionally, you'd want to also uncheck this when the level changes again to another value.
3. Update your validation rule so it says:
   AND($Profile.Name <> 'System Administrator', Record_Locked__c = true)

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You can do that with a combination of two validation rules working on current fields

Vallidation Rule 1

Prevent making any changes when Level equals Archived or Closed unless User is a Sys Admin. Needed to exclude situation when changes are done to Level because otherwise it will not allow to enter Archived or Closed. PRIORVALUE seems to not work here so I used ISCHANGED function to capture that.

AND(
   $Profile.Name <> 'System Administrator',
   NOT(ISCHANGED(Level__c)),
   OR(
      ISPICKVAL(Level__c, 'Archived'),
      ISPICKVAL(Level__c, 'Closed')
   )
)

The thing is that this rules allows making changes if User at the same time changes Level__c. That's why we need second Validation rule.

Vallidation Rule 2

Prevents User from changing Level__c once it is Archived or Closed, unless he is a Sys Admin

AND(
   $Profile.Name <> 'System Administrator',
   ISCHANGED(Level__c),
   OR(
      ISPICKVAL(PRIORVALUE(Level__c), 'Archived'),
      ISPICKVAL(PRIORVALUE(Level__c), 'Closed')
   )
)