ER Notation — Orders Schema

{
  "nodes": [
    { "id":"cu","type":"er-entity","label":"CUSTOMER","x":40,"y":200,"bold":true },
    { "id":"r1","type":"er-relationship","label":"places","x":240,"y":195 },
    { "id":"or","type":"er-entity","label":"ORDER","x":420,"y":200,"bold":true },
    { "id":"r2","type":"er-relationship","label":"contains","x":600,"y":195 },
    { "id":"li","type":"er-weak-entity","label":"LINE ITEM","x":780,"y":200,"bold":true },
    { "id":"r3","type":"er-relationship","label":"for","x":780,"y":340 },
    { "id":"pr","type":"er-entity","label":"PRODUCT","x":960,"y":340,"bold":true },
    { "id":"a1","type":"er-attribute","label":"id (PK)","x":40,"y":80 },
    { "id":"a2","type":"er-attribute","label":"email","x":160,"y":40 },
    { "id":"a3","type":"er-attribute","label":"id (PK)","x":420,"y":80 },
    { "id":"a4","type":"er-attribute","label":"total","x":540,"y":40 },
    { "id":"a5","type":"er-attribute","label":"qty","x":780,"y":80 },
    { "id":"a6","type":"er-attribute","label":"sku (PK)","x":960,"y":460 }
  ],
  "edges": [
    { "id":"e1","source":"cu","target":"r1" },
    { "id":"e2","source":"r1","target":"or","label":"1..*" },
    { "id":"e3","source":"or","target":"r2" },
    { "id":"e4","source":"r2","target":"li","label":"1..*" },
    { "id":"e5","source":"li","target":"r3" },
    { "id":"e6","source":"r3","target":"pr","label":"*..1" },
    { "id":"a","source":"cu","target":"a1","arrowEnd":false },
    { "id":"b","source":"cu","target":"a2","arrowEnd":false },
    { "id":"c","source":"or","target":"a3","arrowEnd":false },
    { "id":"d","source":"or","target":"a4","arrowEnd":false },
    { "id":"e","source":"li","target":"a5","arrowEnd":false },
    { "id":"f","source":"pr","target":"a6","arrowEnd":false }
  ]
}