I need to add a number to the Contract_Line__c record that is created in the trigger below.

It cannot be the same number (cl.Line_No__c) as another Contract_Line__c record that is associated with the same Contract_Header__c record that this new one that is created is associated with.

It needs to start with 1 - and then go from there.

Example:

Each Contract_Line__c record created is also associated with a Contract_Header__c record - which is inherited from the Asset record.

If I create one Contract_Line__c record, and it has Contract_Line__c.Line_No__c = '1' - and it's associated with Contract_Header__c record 'XXX1'

The next Contract_Line__c record that is created (and associated with Contract_Header__c record 'XXX1') should then have a Contract_Line__c.Line_No__c = '2'

and so on...

Further:

When a Contract_Line__c record then has an End Date (Contract_Line__c.End_Date__c = Today or before), it should be removed from this sequence - and all other Contract_Line__c.Line_No__c should be updated with new numbers starting at the number 1.

Can I do that?

Does that make sense?

Thanks for any help.

trigger Asset on Asset (after update) {

    List <Contract_Line__c> contractLines = new List <Contract_Line__c> ();
    Map <Id, Asset> oldmap = new Map <Id, Asset>();
    Map <Id, Asset> newmap = new Map <Id, Asset>();

    //System.debug('Chris in trigger');
    if(Constants.ASSET_FIRST_RUN == False){ }else 
    for(Asset a: Trigger.new) 
    {
    //System.debug('Chris in asset loop')
    if ((Trigger.oldMap.get(a.Id).Status != Trigger.newMap.get(a.Id).Status) && Trigger.newMap.get(a.Id).Status == 'Active')
        { 
        //System.debug('Chris in status changed');
        Contract_Line__c cl = new Contract_Line__c ();
        cl.Asset__c = a.Id;
        cl.Line_No__c = 
        //need to add new number for the Line Number (cl.Line__c) on Contract Line
        //but make sure it's not the same number as one that was already existing for this Contract_Header__c
        
        //System.debug('Chris creating new contract line and adding to list');
        contractLines.add(cl);
        }
        Constants.ASSET_FIRST_RUN = False;      
    }

    if(contractLines.size()>0)
    {
    //System.debug('Chris has values to insert = '+ contractLines.size());
    try
     {
        insert contractLines;
     }
     catch (System.Dmlexception e)  
     {
        system.debug (e); 
     }
    }
}