Question

I have 2 tables in my MySQL DB where column “campaignid” in table “pages” refference (= to) column “id” in the table “campaigns.

ALTER TABLE pages ADD FOREIGN KEY (campaignid) REFERENCES campaigns(id);

The data in these columns is called by this public function:

public function get_pages_by_campaign_id($campaignID) {
    $campaignID = $this->real_escape_string($campaignID);
    return $this->query("SELECT pid, campaignid FROM pages campaigns WHERE campaignid = 'campaigns.id'");
}

However when I try to delete a “page” using:

 public function delete_page($pageID) {
    $this->query("DELETE FROM pages WHERE id = " . $pageID);
}

Nothing happens. Should I have set something like ON DELETE SET NULL | ON UPDATE CASCADE or something????

At the moment I cannot update, delete or save anything to the DB, which has been the case for 2 days now … any help would be Greatly Appreciated!

Answer 1

Your syntax is incorrect. Your query uses campaignid = 'campaigns.id' but the quotes indicate that is a variable, when I assume its the column you’re looking for. You need commas between the table names. You also don’t use the variable you pass into the function.

public function get_pages_by_campaign_id($campaignID) {
    $campaignID = $this->real_escape_string($campaignID);
    return $this->query("SELECT pid, campaignid FROM pages, campaigns WHERE campaignid= campaigns.id AND campaignid = '$campaignID' ");
}

I assume you want to get data from the campaigns table in your query too? Otherwise you don’t need to include it in the query.

EDIT: AS stated in the comments you use id in your delete – should that be pid like you use in the select? Also, put quotes around the variable (not necessary but prevents DB error is the variable is empty)

$this->query("DELETE FROM pages WHERE pid = '" . $pageID. "'");