The logic we need to have to update these 2 fields are:

 

• If the Next PM Date is in the current month (e.g. incoming inspections):

o   Set Last Scheduled date equal to today’s date

o   If Effective PM Schedule Type = fixed, Set Next PM date equal to the newly calculated Last Scheduled date + Effective frequency

• If the Next PM Date is before the current month (e.g. regularly scheduled PM’s):

o   Set Last Scheduled date equal to today’s date+ 1 month (because that’s when the PM will actually be due)

o   Again, if Effective PM Schedule Type = fixed, set Next PM date equal to the newly calculated Last Scheduled date + Effective frequency

global class createPMWorkOrder implements Database.Batchable<sObject>{
    
    public String query;
    
    //Override start method of Database.Batchable interface
    global Database.QueryLocator start(Database.BatchableContext BC){
        //Get Current Date
        date currentDate = Date.today();

        date periodStart;
     
        date periodEnd;
        
        //****Calculate Period Start and End Dates
        if(currentDate.month() == 12)
            periodStart = date.newInstance(currentDate.year()+1, 1, 1);
        else
            periodStart = date.newInstance(currentDate.year(), currentDate.month()+1, 1);
        //periodStart = Date.today()-1;
        periodEnd = periodStart.addMonths(1) - 1;
            
        /****Create a query for retrieving all the fields required for creating a work order
             using the conditions Next_PM_Date__c is between Period Start and End Dates and Asset is active?*/
        //String returnQuery = 'Select id, Facility__c, Primary_FSE__c, PM_Plan__c, Next_PM_Date__c, Effective_PM_Frequency__c, Last_Completed_PM_Date__c, Last_Scheduled_PM_Date__c, Facility__r.OwnerId from MVS_Asset__c where (Next_PM_Date__c >= :periodStart and Next_PM_Date__c <= :periodEnd) and Status__c = \'Active\'';
        
        return Database.getQueryLocator(query);
    }
    
    //Override execute method of Database.Batchable interface
    global void execute(Database.BatchableContext BC, List<MVS_Asset__c> assets){

        List<Case> pmWorkOrders = new List<Case> ();
        List<MVS_Asset__c> mvsAssetList = new List<MVS_Asset__c>();
        
        //Get Record Type ID of Preventative Maintenance
        RecordType RecType = [select id from RecordType where name = 'Preventative Maintenance' and SobjectType = 'Case'];
        
        //Create Work Orders for all the assets in the context
        for (MVS_Asset__c mvsAsset : assets){
            //Determine Work Order Owner
            Id workOrderOwner = mvsAsset.Primary_FSE__c;
            if (workOrderOwner == null){
                workOrderOwner = mvsAsset.Facility__r.OwnerId;
            }
            
            //Initiate a Work Order
            Case pmWorkOrder = new Case (   OwnerId = workOrderOwner,
                                            MVS_Asset__c = mvsAsset.Id,
                                            AccountId = mvsAsset.Facility__c,
                                            Status = 'Open',
                                            Priority = 'Schedule Activity',
                                            RecordTypeId = RecType.Id);
            //Add Work Order to the list                                
            pmWorkOrders.add(pmWorkOrder);
            
            //Assigning the List values to variables for better performance
            //date lastScPMDate = mvsAsset.Last_Scheduled_PM_Date__c;
            //date nextPMDate = mvsAsset.Next_PM_Date__c;
            //date lastComPMDate = mvsAsset.Last_Completed_PM_Date__c;
            String effectivePMFreq = mvsAsset.Effective_PM_Frequency__c;
            
            //Assign Last Scheduled PM Date to Next PM Date
            //mvsAsset.Last_Scheduled_PM_Date__c = mvsAsset.Next_PM_Date__c;
            
            mvsAsset.Last_Scheduled_PM_Date__c = System.today();

            Integer effPMFrequency = 0;
            if (effectivePMFreq != 'Manufacturer\'s Recommendation' && effectivePMFreq!='Not Required')
                effPMFrequency = decimal.valueOf(effectivePMFreq).intValue();
            
            //Calculate Next PM Date    
            if (mvsAsset.Effective_PM_Schedule_Type__c == 'Float')
                mvsAsset.Next_PM_Date__c = null;
            else{
                mvsAsset.Next_PM_Date__c = System.today().addMonths(effPMFrequency);
            }
                
            mvsAsset.Outstanding_PM_Work_Order__c = true;
            /*if (mvsAsset.PM_Schedule_Type__c == 'Floating'){
                if(mvsAsset.Last_Completed_PM_Date__c != null)
                    mvsAsset.Next_PM_Date__c = mvsAsset.Last_Completed_PM_Date__c.addMonths(effPMFrequency);
                else
                    mvsAsset.Next_PM_Date__c = nextPMDate.addMonths(effPMFrequency);
            }
            else{
                if(lastScPMDate != null)
                    mvsAsset.Next_PM_Date__c = lastScPMDate.addMonths(effPMFrequency);
                else
                    mvsAsset.Next_PM_Date__c = nextPMDate.addMonths(effPMFrequency);
            }*/
            

 if ( mvsAsset.Next_PM_Date__c == currentDate.month)                        mvsAsset.Last_Scheduled_PM_Date__c = System.today();                      mvsAssetList.add(mvsAsset); } System.debug('*******************************Updating MVS Asset'); //Insert all new Work Orders update mvsAssetList; System.debug('*********************************Inserting Work Orders'); insert pmWorkOrders; } //Override finish method of Database.Batchable interface global void finish(Database.BatchableContext BC){ } }

 i am trying the above highlited code.. i am getting error

 

kindly help