Call to a member function bind_param() on a non-ob

问题:

This question already has an answer here:

• Issues with mysqli::prepare() and bind_param() [closed] 2 answers

I'm receiving the error above in the get_template() function of my class listed below. Does anyone know why I am receiveing this error? All of the other queries execute fine and $template_number is definitely returning an int which is expected at this point in the query so why am I receiving this error? Could it be because the return on this query is formatted as TEXT in MySQL (and appears as a BLOB in PHPMyAdmin?

    class Page{

private $con; 

public function __construct(Connection $con) {
    $this->con = $con;
    if(isset($_GET['id'])){
    $id = $_GET['id'];
    }else{      
    $id = 1;
    }       
    $this->get_headers($id);
    $this->get_content($id);
    $this->get_footer($id);
}

private function get_headers($pageId){ 
    $retrieveHead = $this->con->prepare("SELECT headers FROM pages WHERE page_id=?");
    $retrieveHead->bind_param('i',$pageId);
    $retrieveHead->execute();
    $retrieveHead->bind_result($header);
    $retrieveHead->fetch();
    $retrieveHead->close();
    echo $header;   
}

private function get_footer($pageId){ 
    $retrieveFooter = $this->con->prepare("SELECT footer FROM pages WHERE page_id=?");
    $retrieveFooter->bind_param('i',$pageId);
    $retrieveFooter->execute();
    $retrieveFooter->bind_result($footer);
    $retrieveFooter->fetch();
    $retrieveFooter->close();
    echo $footer;   
}

private function get_content($pageId){
    $retreiveContent = $this->con->prepare("SELECT template_id, section_title, i1, i2 FROM content WHERE page_id=? ORDER BY sequence DESC");
    $retreiveContent->bind_param('i',$pageId);
    $retreiveContent->execute();
    $retreiveContent->bind_result($template_id, $section_title, $i1, $i2);
         while ($retreiveContent->fetch()) {
            //Variables will be populated for this row.
            //Update the tags in the template.
            $template = $this->get_template($template_id);
            $template = str_replace('[i1]',$i1,$template);
            $template = str_replace('[i2]',$i2,$template);
            //$theTemplate is populated with content. Probably want to echo here
            echo $template;
        }
    $retreiveContent->close();
}

private function get_template($template_number){
    $retreiveFunction = $this->con->prepare("SELECT code FROM templates WHERE template_id=?");
    $retreiveFunction->bind_param('i',$template_number);
    $retreiveFunction->execute();
    $retreiveFunction->bind_result($template);
    $retreiveFunction->fetch();
    $retreiveFunction->close();
    return $template;
}

}

Table structure can be found below:

回答1:

See here and here. mysqli_stmt::execute() by default stores the results server side and fetches row by row unless you call mysqli_stmt::store_result() to buffer them client side. Attempting to prepare another statement most likely fails while there are unfetched reults server side from a previous statement.

回答2:

For anyone else searching for this solution, as bwewsing suggests I needed to add in store_result however from the links provided above it's not too clear where this should be implemented.

Implementation should take place in the initial calling method. So, as the get_content() method calls the get_template() method it should be implemented here in the following manner:

    private function get_content($pageId){
    $retreiveContent = $this->con->prepare("SELECT template_id, section_title, i1, i2 FROM content WHERE page_id=? ORDER BY sequence DESC");
    $retreiveContent->bind_param('i',$pageId);
    $retreiveContent->execute();
    $retreiveContent->bind_result($template_id, $section_title, $i1, $i2);
    $retreiveContent->store_result();
         while ($retreiveContent->fetch()) {
            //Variables will be populated for this row.
            //Update the tags in the template.
            $template = $this->get_template($template_id);
            $template = str_replace('[i1]',$i1,$template);
            $template = str_replace('[i2]',$i2,$template);
            //$theTemplate is populated with content. Probably want to echo here
            echo $template;
        }
    $retreiveContent->free_result();    
    $retreiveContent->close();
}