Keep obtaining a constraint breach?

This really is my schema.yml.

Products:
  columns:
    title: { type:string(35) }
    img_path: { type: string(100) }
    is_activated: { type: boolean, notnull: true, default: 0 }
    price: { type: integer, notnull: true }


Auctions:
  columns:
    pid: { type: bigint }
    last_bider: { type: bigint }
    starts_at: { type: timestamp, notnull: true }
    ends_at: { type: timestamp, notnull: true }
  relations:
    Products:
      local: pid
      foreign: id
    User:
      local: last_bider
      foreign: id


User:
  columns:
    username: { type: string(20) }

In fittings.yml

Products:
  my_pendant:
    title: 1 Gram Gold Rose Pendant
    img_path: test/pendant.jpg
    is_activated: 1
    price: 25

User:
  username1:
    username: denis

Auctions:
  pendant_auc:
    pid: my_pendant
    last_bider: username1
    starts_at: 2011-26-06
    ends_at: 2011-28-06

I keep getting constraint breach: Cannot add or update child row on 'pid' and 'id' - relation between Auctions and Items when attempting to place the fixture in to the database.

I am using doctrine... and that i can't understand why this really is happening.