Updating many item using same id in grails

I am saving values in two tables asset and asset_history.On creating asset i am saving values in asset table if any update i wantthat time it as to store in asset and asset_history on id bases . Now i want to get two tables value in edit page for getting asset_history i used sql query to get values in asset_history.all are working well and fine but it is coming in array list values(all update list is showing in single row).when i updata values in edit page it should save and show in different rows in asset_history. for that i used for loop but it not getting values.

asset table i have these fields :-

     id
      asset_title
      asset_description
      client_id
      comment
      status
etc...

In asset_history field:-

id
comment
update_on
update_by
status

If any update in asset field.The update list should save in both asset and asset_history.I have used a query to update(as shown below). But it is getting arraylist in asset_history table.

edit action

    def dataSource
def edit={
    def assetInstance = Asset.get(params.id)
        if (!assetInstance) { 

            flash.message = "${message(code: 'default.not.found.message', args: [message(code: 'asset.label', default: 'Asset'), params.id])}"
            redirect(action: "list")
        }
        else {  Sql sql = new Sql(dataSource) 
             def result = sql.rows("SELECT * from asset_history where id ='"+params.id+"' ")
            //def n=result

            /*  def arr = (String[])result
                        for(i in 0 .. result.size()-1)
                         {

            return [assetInstance: assetInstance,result:i]
                         }*/
                   return [assetInstance: assetInstance,result: result]
        }

    }

In edit.gsp

<tbody>

                        <tr>


                          <td>${result.id}</br></td>
                            <td>${result.comment}</br></td>

                            <td>${result.update_on}</br></td>
                           <td>${result.update_time}</br></td>
                               <td>${result.update_by}</br></td>

                        </tr>

                    </tbody>

In asset_history table the values are getting in arraylist and showing updated list in single row.But i want show it in separate row ,when i update each time.I used for-loop for this but it is not working.Please guide me to solve this problem.

Solution

Your problem is that you can only return one value from a function in Groovy (and in all other languages I know anyway). So the first iteration in your for loop returns and the following iterations (where you expect to return more instances) are not executed.

You must return a list and use a <g:each> tag in your GSP file (which is the equivalent to a for loop in GSP):

def edit = {
  def assetInstance = Asset.get(params.id)
  if (!assetInstance) {
    flash.message = "${message(code: 'default.not.found.message', args: [message(code: 'asset.label', default: 'Asset'), params.id])}"
    redirect(action: "list")
  }
  Sql sql = new Sql(dataSource) 
  def results = sql.rows("SELECT * from asset_history where id ='" + params.id + "' ")
  return [results: results]
}

And your GSP:

<tbody>
  <g:each var="result" in="${result}">
    <tr>
      <td>${result.id}</br></td>
      <td>${result.comment}</br></td>

      <td>${result.update_on}</br></td>
      <td>${result.update_time}</br></td>
      <td>${result.update_by}</br></td>
    </tr>
  </g:each>
</tbody>

As a bonus, here are a few tips that will make your application look better:

Don't return values if you don't use them in your GSP, like assertInstance here
Avoid using SQL and prefer relying on Grails built-in access methods (findBy) or Hibernate Criteria if your assert history are Grails domain objects. This will give you Grails objects backs instead of raw SQL rows
Indent your code correctly for readability. Chances are that your IDE have a feature that can do that for you.