I had to display the Opportunity fields and it's related all invoices and invoice line items fields in one visual force page

so i can edit any field it had to be updated in it's related object fields i had tried the code but it's not working properly can u give me the correction of the controller

<apex:page controller="vfediting"><apex:pageBlock title="Opportunity" id="op2">

<apex:form id="f1" > <apex:outputPanel rendered="{!table1}">

 <apex:pageBlockTable value="{!op}" var="o">

 <apex:column headerValue="Action"/>

<apex:column >       

     <apex:outputLink value="/{!o.id}/e?retURL=/apex/{!$CurrentPage.Name}">Edit</apex:outputLink> 

       </apex:column>  

<apex:column value="{!o.name}"/> 

<apex:column value="{!o.Invoice_Quantity__c}"/> 

<apex:column value="{!o.Invoice_Status__c}"/> 

<apex:column value="{!o.Invoice_Total__c}"/> 

<apex:column value="{!o.DeliveryInstallationStatus__c}"/>

 <apex:column value="{!o.Fully_Paid_Invoices_total__c}"/> 

<apex:column value="{!o.Open_Invoices_Total__c}"/>

 <apex:column value="{!o.Partially_Paid_Invoices_Total__c}"/>

 <apex:column value="{!o.Total_Invoiced_Amount__c}"/>

 <apex:column value="{!o.Total_Invoice_Quantity__c}"/>

  </apex:pageBlockTable><apex:pageBlockTable value="{!inv}" var="i1">

<apex:column value="{!i1.name}">

</apex:column>

<apex:column value="{!i1.Delivery_Installation_Status__c}"></apex:column>

<apex:column value="{!i1.Fully_Paid_Invoices_total__c}"></apex:column>

<apex:column value="{!i1.Invoice_Date__c}"></apex:column>

<apex:column value="{!i1.Invoice_Quantity__c}"></apex:column>

<apex:column value="{!i1.Total_Invoiced_Amount__c}"></apex:column>

<apex:column value="{!i1.Invoice_Status__c}"></apex:column>

<apex:column value="{!i1.Invoice_Total__c}"></apex:column>

<apex:column value="{!i1.Open_Invoices_Total__c}"></apex:column>

<apex:column value="{!i1.Opportunity__c}"></apex:column>

<apex:column value="{!i1.Partially_Paid_Invoices_Total__c}"></apex:column>

</apex:pageBlockTable>

<apex:pageBlockTable value="{!invlt}" var="il2">

<apex:column value="{!il2.name}"></apex:column>

<apex:column value="{!il2.Invoice__c}"></apex:column

><apex:column value="{!il2.Price__c}"></apex:column>

<apex:column value="{!il2.Product__c}"></apex:column>

<apex:column value="{!il2.Qty__c}"></apex:column>

<apex:column value="{!il2.Total__c}"></apex:column>

</apex:pageBlockTable>

</apex:outputPanel>
 <apex:outputPanel rendered="{!table2}">

 <apex:pageBlockTable value="{!oplist}" var="o"> 

<apex:column value="{!o.name}"/> 

<apex:column value="{!o.Invoice_Quantity__c}"/> 

<apex:column value="{!o.Invoice_Status__c}"/>

 <apex:column value="{!o.Invoice_Total__c}"/> 

<apex:column value="{!o.DeliveryInstallationStatus__c}"/>

 <apex:column value="{!o.Fully_Paid_Invoices_total__c}"/>

 <apex:column value="{!o.Open_Invoices_Total__c}"/>

<apex:column value="{!o.Partially_Paid_Invoices_Total__c}"/>

 <apex:column value="{!o.Total_Invoiced_Amount__c}"/> 

<apex:column value="{!o.Total_Invoice_Quantity__c}"/> 

</apex:pageBlockTable><apex:pageBlockTable value="{!inv}" var="i1">

<apex:column headerValue="Action"/>
<apex:column ><apex:commandLink value="save" action="{!save}"/></apex:column>
<apex:column value="{!i1.name}"/>

<apex:column value="{!i1.Delivery_Installation_Status__c}"/>

<apex:column value="{!i1.Fully_Paid_Invoices_total__c}"/>

<apex:column value="{!i1.Invoice_Date__c}"/>

<apex:column value="{!i1.Invoice_Quantity__c}"/>

<apex:column value="{!i1.Total_Invoiced_Amount__c}"/>

<apex:column value="{!i1.Invoice_Status__c}"/>

<apex:column value="{!i1.Invoice_Total__c}"/>

<apex:column value="{!i1.Open_Invoices_Total__c}"/><apex:column value="{!i1.Opportunity__c}"/><apex:column value="{!i1.Partially_Paid_Invoices_Total__c}"/><apex:column value="{!i1.Total_Invoice_Quantity__c}"/><apex:column value="{!i1.Total_Invoice_Quantity__c}"></apex:column></apex:pageBlockTable><apex:pageBlockTable value="{!invlt}" var="il2"><apex:column value="{!il2.name}"></apex:column><apex:column value="{!il2.Invoice__c}"></apex:column><apex:column value="{!il2.Price__c}"></apex:column><apex:column value="{!il2.Product__c}"></apex:column><apex:column value="{!il2.Qty__c}"></apex:column><apex:column value="{!il2.Total__c}">

</apex:column></apex:pageBlockTable></apex:outputPanel>
</apex:form>

</apex:pageBlock> 

 </apex:page>

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public with sharing class vfediting {
   
public Opportunity op{get; set;}public list<invoice__c> inv{get; set;}public list<Invoice_Line_Item__c> invlt{get; set;}

         public vfediting() 

   {          op=[select id,name,Invoice_Quantity__c,Invoice_Status__c,Invoice_Total__c,DeliveryInstallationStatus__c ,Fully_Paid_Invoices_total__c,Open_Invoices_Total__c,Partially_Paid_Invoices_Total__c,Total_Invoiced_Amount__c, Total_Invoice_Quantity__c from Opportunity where id=:ApexPages.currentPage().getParameters().get('id')];   inv=[select id,name,Delivery_Installation_Status__c,Fully_Paid_Invoices_total__c,Invoice_Date__c,Invoice_Quantity__c, Invoice_Status__c,Invoice_Total__c,Open_Invoices_Total__c,Opportunity__c,Partially_Paid_Invoices_Total__c, Total_Invoiced_Amount__c,Total_Invoice_Quantity__c from invoice__c where opportunity__c=:op.id];   invlt=[select id,name,Invoice__c,Price__c,Product__c,Qty__c,Total__c from Invoice_Line_Item__c where invoice__c=:inv[0].id];              }     

   public PageReference save() {        table2=false;        table1=true;        update inv;        update invlt;        return null;    }

    public boolean getTable2() {        return Table2;    }

 boolean Table1=true; boolean Table2=false; public boolean gettable1(){ return table1; } 

    public PageReference edit() {      table1=false;      table2=true;      return null;  } 

  public PageReference Invoices()  {   return null;   PageReference customPage = new PageReference('006/o'); //customPage.getParameters().put('id', i.ID);customPage.setRedirect(true); //return(new ApexPages.StandardController(i)).view();return customPage;
 }

}

I'm getting error can u guide me the r8 controller