Lets you define the fields that create a join between SQL tables.
<join> element can only be used if the parent
<element> element is of ‘link’ type. This means that the parent element must have the “@type=link” attribute declared.
It is not necessary to specify the name and namespace of the remote table in the
<join> element. They need to be specified in the parent
By convention, links are defined at the end of the schema.
<join> element isn’t specified when the link type element is defined, the link will automatically be placed on the primary keys of both tables.
Link between the ‘email’ field of the current table and the “@compagny-id” field of the remote table:
<join xpath-dst="@compagny-id" xpath-src="@email"/>
Filtered link towards the “cus:Country” table based on the content of the “@country” field which must contain the ‘EN’ value:
<element name="StockEN" type="link" label="MyLink" target="cus:Stock"> <join xpath-dst="@country" xpath-src="@code" dstFilterExpr="@country = 'EN'"/> </element>