title: Parent key not found, but exists oracle DB
body: <p>Before I get started with the error message I want to show a simple left join query for my vendor and product tables:</p>
  
  <pre><code>select p.id as ProductId, p.vendorid as VendorFk, v.id as VendorPk
      from Vendors v
          left join products p
          on v.id = p.vendorid;
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/Huiex.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Huiex.png" alt="enter image description here"></a></p>
  
  <p>I ran a similar insert to the one below with success five times prior as you can see by the image above. On try number 6 it seems to fail. I'm not really sure why. I'm brand new to Oracle, i've never had a problem like this before with MS SQL server. Any help would be greatly appreciated. Also I'm using Oracle SQL Developer.</p>
  
  <p>-"Error report -
  ORA-02291: integrity constraint (SYSTEM.FK_VENDORS_ID) violated - parent key not found"</p>
  
  <pre><code>insert into products(cost , id , name , partnumber , VendorId)
  values(99.99, 6, 'xbox', 'xbox1', 2);
  </code></pre>