How to put DML operation outside the for loop?

Question

I wrote one for loop and perform insert,update operation inside the for loop, it is working clearly but i need to perform that operation outside the for loop so is the better way to do it ?

for(Exhibition_Line_Item__c ELI : [Select Item__c, Line_Total__c,Invoice_Line__c, Line_Description__c,Exhibitor__c from Exhibition_Line_Item__c where Exhibitor__c in : exIdList]){

            invLine = new Invoice_Line__c();
            if(ELI.Line_Description__c != null){
                invLine.Line_Description__c = ELI.Item__c +' : '+ ELI.Line_Description__c;
            }else{
                invLine.Line_Description__c = ELI.Item__c;
            }
            invLine.Line_Total__c =  ELI.Line_Total__c;
            invLine.invoice__c = invoiceExhibitor.get(ELI.Exhibitor__c).Invoice__c;

            insert invLine;

            Invoice_Line__c inLI = new Invoice_Line__c();
            inLI = [select Id, Name from Invoice_Line__c where id =: invLine.Id];
            ELI.Invoice_Line__c = inLI.Id;

            update ELI;

            if(invIDs == null){
                invIDs = invoiceExhibitor.get(ELI.Exhibitor__c).Invoice__c;
            }else{
                invIDs += ',' + invoiceExhibitor.get(ELI.Exhibitor__c).Invoice__c;  
            }
}

Answer 1

Create one List called exLineList

Create one List called invLineList

exLineList = new List<Exhibition_Line_Item__c>();
invLineList= new List<Invoice_Line__c>();     

        for(Exhibition_Line_Item__c ELI : [Select Item__c, Line_Total__c,Invoice_Line__c, Line_Description__c,Exhibitor__c from Exhibition_Line_Item__c where Exhibitor__c in : exIdList]){

            invLine = new Invoice_Line__c();
            if(ELI.Line_Description__c != null){
                invLine.Line_Description__c = ELI.Item__c +' : '+ ELI.Line_Description__c;
            }else{
                invLine.Line_Description__c = ELI.Item__c;
            }
            invLine.Line_Total__c =  ELI.Line_Total__c;
            invLine.invoice__c = invoiceExhibitor.get(ELI.Exhibitor__c).Invoice__c;
            invLineList.add(invLine);
            exLineList.add(ELI);
            if(invIDs == null){
                invIDs = invoiceExhibitor.get(ELI.Exhibitor__c).Invoice__c;
            }else{
                invIDs += ',' + invoiceExhibitor.get(ELI.Exhibitor__c).Invoice__c;  
            }

        }

        insert invLineList;

        if(invLineList.size() > 0){
            for(integer i = 0 ; i < invLineList.size() ; i++ )
            {
                exLineList.get(i).Invoice_Line__c = invLineList.get(i).Id;
            }
            update exLineList;
        }