Primary key
Primary keys are unique identifiers for a data object and can be used to create a relationship between data objects. For every data object, there can be only one primary key.
To make the logical data dictionary a primary key, click the three dots next to the logical data dictionary in the data object and then click Change primary key.
Establish a relationship between primary keys
Establish a relationship by dragging the primary key from one data object to another data object with which you want to establish a relationship.
Change/delete a primary key without a relationship present
If a primary key doesn't have a relationship, it can be easily changed. Click the three dots next to the logical data dictionary in the data object and then click Change primary key. The primary key is then disconnected from this logical data dictionary. Now you can add the primary key to another logical data dictionary.
Change a primary key with a relationship present
In case a relationship exists, the action remains the same as described. Click the three dots next to the logical data dictionary and click Change primary key. After this action, a pop-up window with a warning will appear. This indicates that there are relationships present from the primary key to a data object(s). If you still delete the primary key, the relationship jumps to the top or bottom of the data object. The relationship therefore remains visible. It is not desirable to have a relationship that is not established between primary keys.
Make a relationship between data objects
It is possible to establish a relationship between data objects without primary keys. You can create a relationship by using the magic stick. This relationship appears at the top or bottom of the data object.
Note: Whenever possible, avoid establishing this relationship as the goal is to connect primary keys rather than data objects.
Relationship types
There are four possible relationships between primary keys. Adjust a relationship by right-clicking on one of the two black dots next to the data object. The following options appear:
- One and only one
- One or many
- Zero or one
- Zero or more
Adjust both black dots by choosing an option, after which the relationship is complete.
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