graph{
  start=42

  // Entities
  node [
    shape=box
    style=filled
    penwidth=1.5
    fillcolor="#FFFFFF"
  ]
  1 [label="Voilier"]
  5 [label="Semaine"]
  6 [label="Réservation"]

  // Normal entity attributes
  node [
    shape=oval
    penwidth=1.5
    fillcolor="#FFFFFF"
  ]
  3 [label="longueur"]
  9 [label="date\ndébut"]
  11 [label="arrhes"]
  12 [label="date résa"]

  // Weak and strong entity attributes
  2 [label=<<u>num<br/>voilier</u>>]
  8 [label=<<u>num<br/>semaine</u>>]
  10 [label=<<u>num résa</u>>]

  // Relationship attributes
  node [
    fillcolor="#FFFFFF"
  ]
  7 [label="tarif"]

  // Relationships
  node [
    shape=diamond
    height=0.7
    penwidth=1.5
    fillcolor="#FFFFFF"
  ]
  4 [label="Offrir"]

  // Edges between entities and attributes
  edge [
    penwidth=1.5
  ]
  1 -- 2
  1 -- 3
  5 -- 8
  5 -- 9
  6 -- 10
  6 -- 11
  6 -- 12

  // Edges between relationships and attributes
  edge [color="#000000"]
  4 -- 7

  // Edges between entities and relationships
  edge [
    penwidth=1
    color="#000000:#000000"
    labeldistance=2
    headlabel=1
  ]
  6 -- 4
  edge [headlabel=N]
  1 -- 4 [color="#000000"]
  5 -- 4 [color="#000000"]
}