laravel一对一的关系

Question

I have xml_document table with these columns:

id
general_information_id

I have general_information table with these columns:

id
domain
log_file

The relationship between them is one to one.

Have I build the relationship correctly? Or I need to add xml_document_id column to the general_information table.

Secondly:

I have added a row to the xml_doucment and now I want to add a row to the general_information and link this new row to the xml_document

I tried this:

 $xmlDocument = XmlDocument::find(Input::get(4));
            $generalInformation = new GeneralInformation($dataGeneralInformation);
            $generalInformation->xmlDocument()->associate($xmlDocument);
            //$xmlDocument->generalInformation()->attach($generalInformation);
            $generalInformation->save();
            $xmlDocument->save();

but I got error that xml_document_id column doesn't exist in the general_information table.

I tried to replace associate with attach but I got that attach is not an existed function.

please help me I am tried of this one to one relationship, I couldn't know what is the correct way to do id. I don't know where to add columns in the database and what to do in the models. I have tried a lot of things but still so confused.

Update 1

class GeneralInformation extends  Eloquent{
.....   
public function xmlDocument(){
        return $this->belongsTo('XmlDocument');
    }
}


class XmlDocument extends Eloquent {
....
 public  function  generalInformation(){
        return $this->hasOne('GeneralInformation','general_information_id');
    }
}

Answer 1

To make a one-to-one relationship, you need to store the primary key of parent table in the child table as a foreign key. So if xml_document is parent and if it contains many general_information then the id field of the xml_document should be present in in the general_information table as xml_document_id.

So, you may build the one-to-one relation like this:

// xml_document model
public function generalInfo()
{
    return $this->hasOne('GeneralInformation');
}

Then the declare the GeneralInformation model.