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Jira is able to link issues both within the same project and across different projects. The link referred to here is essentially a normal Internet hyperlink, with an added custom field, "link type," to explain the logical relationship between the linked issues. Any time a Jira issue ID is entered into a text field or a comment on a Jira issue, a link will automatically be generated.
Generally only two link types are used in the OLE testing process: the "Parent Jira" link and the "Tests/Tested By" link, explained below in more detail.
Parent Jira
The link used between Stories and Test Cases is the "Parent Jira" link. This is a one-way link declaring that the Story is the parent to the Test Case. The link will only be shown on the Test Case, not the Story. One Story may be the parent to many Test Cases, but a Test Case will not have more than one parent.
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