Toad Data Modeler 6.5 - User Guide

Create Keys

An entity can have a primary key and many alternate keys. The keys are stored in the Keys tab in the Entity Properties form.

To create a key

• Right-click an entity on the Workspace and select Add | Key. The Key Properties dialog opens.

To create a PK (unique) attribute

1. Right-click an entity on the Workspace and select Add | Attribute. The Attribute Properties dialog opens.
2. On tab General, select the Primary Key (Unique) checkbox.

To assign an attribute to key

• In the Entity Properties dialog, Attributes tab, double-click the empty space in the Key column next to the selected attribute.

or

• In the Key Properties dialog | Attributes tab.

NotNull Property for PK and AK Attributes

Toad Data Modeler allows you to check/uncheck the NotNull property for PK and AK attributes.This is possible only if the Allow Null Attributes in Keys checkbox is selected (unchecked by default).

To select this checkbox

Select Settings | Options | Physical Model and select the checkbox.

If this checkbox is not selected, Toad Data Modeler doesn’t allow you to uncheck the NotNull checkbox in key attributes.

The availability of this option differs by database:

If the Allow Null Attributes in Keys checkbox is selected:

• When you assign an attribute to a key (PK, AK), the Not Null checkbox of the attribute will be checked. (But you are able to uncheck it)
• During propagation of the key via the identifying relationship, the Not Null property in child attribute is inherited from the parent attribute. The only exception is when a database doesn't support Null value in primary key, which would be created via the propagation.
• During Model Conversion, different settings of the Not Null property and its support in different databases are taken into consideration.
• For databases that support Null value in child attribute, the Mandatory Parent checkbox is selected in the Relationship Properties dialog and should behave coherently to Null value in child attribute as well as it behaves for non-identifying relationships.
• For databases that support Null value in child attribute, the settings of the Synchronize NotNull with Mandatory Parent option work the same way for PFK as for FK.

See Synchronization of NotNull and Mandatory Parent for more information.

Edit Keys

• In the Entity Properties dialog | Keys tab | double-click the key.

or

• Find the key in Model Explorer | EntityName folder | Keys | Double-click (or right-click and select Edit).

Delete Keys

• In the Entity Properties form | Keys tab, select a key and click the Delete button.

or

• Find the key in Model Explorer | EntityName folder | Keys | right-click the key and select Delete Item.

Note: It is possible to delete a primary key. It's not possible to delete an alternate key of unique attribute.

Select Parent Key for Relationship

Linking Method

In Toad Data Modeler, you can link parent and child entities:

• Through a Key (Primary or Alternate key) of parent entity
• Through Unique Index of parent entity

To set a linking method

1. Double-click the selected relationship.
2. From the Parent Key box, select the appropriate linking method.