如何在codeigniter中检查两个字段的重复

Question

How to check the duplication of following fields in controller. this is my view code

            <div class="form-group col-lg-12">
            <label class="control-label col-lg-2">Name</label>
            <div class="col-lg-4">
                <select id ="choose" class="form-control" name="name">
                    <option value="">Select One</option>
                    <option value="create_user">New user creation</option>
                    <option value="register_user">New user registration</option>
                    <option value="forgot_password">Forgot Password</option>                        
                </select>
            </div>
            <div class="col-lg-6" id="email_tmpl"></div>
            </div>

            <div class="form-group col-lg-12">
            <label class="control-label col-lg-2">Notification to</label>
            <div class="col-lg-10">
                <select id ="notification" class="form-control" name="notification">
                    <option value="">Select One</option>
                    <option value="User">User</option>
                    <option value="Site Admin">Site Admin</option>
                </select>
            </div>
            </div>

if i selected the option "New user creation" in 1st combo box,then i selected "User" option in next combo box. I want to show an error message when again select the "User" option under "New user creation".And only "Site Admin" can select under "New user creation" option. This is my controller code.

    public function save_email_tmpl()
    {
    $this->load->model("Email_templates");
    $user_data = $this->session->userdata("logged_user");
    $post_data = $this->input->post();

    if($post_data != FALSE )
    {
    $check_name = $this->Email_templates->get_all_records
    ("",array("name" => $post_data["name"]));

        if(count($check_name)< 2)
        {

                $data = array("name" => $post_data["name"],
                    "notification" => $post_data["notification"],
                    "cc" => $post_data["cc"],
                    "subject" => $post_data["subject"],
                    "email_template" => $post_data["email"]);

        $this->Email_templates->insert_record($data,$user_data);
                echo json_encode(array(
                                "status" => "success",
                                "msg" =>  lang("email_tmpl_added")));

        }
        else
        {
            echo json_encode(array(
        "status" => "failed",
        "msg" => lang("invalid_data")));
        }
    }
    else
    {
        echo json_encode(array(
            "status" => "failed",
            "msg" => lang("invalid_data")));
    }
    }

I want to check the condition in this code.