Unique keys

Key items can have individual or group uniqueness:

If key items are defined with individual uniqueness, an InForm user cannot add an instance of a repeating form or itemset in which the value of any key item is identical to the value of that item in another instance. For example, if the DATE and PROCEDURE items are defined as individually unique keys in a repeating form or section, the following table shows how the DATE and PROCEDURE items are evaluated when a user attempts to add new instances.

Example of individual uniqueness in key items

DATE value	PROCEDURE value	Result when data is submitted
May 1, 2009	Hematocrit	Instance or row added
May 1, 2009	Hemoglobin	Instance or row rejected
June 14, 2009	Hematocrit	Instance or row rejected
June 15, 2009	Platelet count	Instance or row added

Note: A set of key items for a repeating form can include both items that are individually unique and items that appear in the drop-down list for navigation but are not used to enforce uniqueness. The key items can come from the repeating form or from a non-repeating section in the form.

If key items are defined with group uniqueness, they make up a composite key. An InForm user cannot add an instance of a repeating form or itemset in which the values of all of the items in the composite key are the same as the values of all of the composite key items in another instance. For example, if the DATE and PROCEDURE items are defined as group unique keys in a repeating form or section, the following table shows how the DATE and PROCEDURE items are evaluated when a user attempts to add new instances.

Example of group uniqueness in key items

DATE value	PROCEDURE value	Result when data is submitted
May 1, 2009	Hematocrit	Instance or row added
May 1, 2009	Hemoglobin	Instance or row added
June 14, 2009	Hematocrit	Instance or row added
May 1, 2009	Hemoglobin	Instance or row rejected

Note: If a group of key items is defined with group uniqueness, no other items in the repeating form or section can be defined as non-unique key items. Only the items that are defined with group uniqueness appear in the drop-down list of a repeating form.