# Select a cardinality notation: IDEF1X, Relational, or Crow's feet

- Select a cardinality notation: IDEF1X, Relational, or Crow's feet
- About relational and IDEF1X notation

## Select a cardinality notation: IDEF1X, Relational, or Crow's feet

- On the
**Database**menu, point to**Options**and then click**Document**. - For IDEF1X or Relational:
- On the
**General**tab, under**Symbol set**click**IDEF1X**or**Relational**. - For Crow's feet:
- On the
**Relationship**tab, under**Show**select the**Crow's feet**check box. - Click
**OK**.

## About IDEF1X, Relational, and Crow's feet notation

There are many different ways to display cardinality (like one-to-many). The **Database Model Diagram** template offers shapes for the two most popular methods: IDEF1X and Relational. Relational notation is selected by default when you open a new database model diagram. Both of these show the properties of relationships by changing the format of the table shapes and the relationship lines.

In addition to those styles you can choose to use the Crow's feet notation with either of them. Crow's feet notation changes only the ends of the relationship lines.

### IDEF1X notation

In IDEF1X notation a solid circle indicates the foreign key side of the relationship (child table). If the child isn't required to have a parent there is an empty diamond at the parent side of the relationship.

Non-identifying relationships are drawn with a dashed line; identifying ones with a solid line.

The cardinality is shown as:

(Blank) | One to zero or more |
---|---|

P | One to one or more |

Z | One to zero or one |

1 | One to exactly one |

Two numbers separated by a dash | a range |

### Relational notation

In Relational notation a solid arrow indicates the parent table.

Identifying relationships are indicated by the foreign key being placed in the top row with both the PK and FK designations.

The cardinality is shown as:

* | One to zero or more |
---|---|

1..* | One to one or more |

0..1 | One to zero or one |

1 | Exactly one |

Two numbers separated by a dash | a range |

### Crow's feet notation

Crow's feet notation indicates the parent table and optionality by using a standard set of marks that can be on either side of the relationship.

Empty circle and crow's foot | Zero or more |
---|---|

Single hatch mark and crow's foot | One or more |

Single hatch mark and empty circle | Zero or one |

Double hatch mark | Exactly one |