join element

Last update: January 6, 2025

Content model

join:==EMPTY

Attributes

  • @dstFilterExpr (string)
  • @xpath-dst (string)
  • @xpath-src (string)

Parents

<element>

Children

None

Description

Lets you define the fields that create a join between SQL tables.

Use and context of use

A <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 <element>.

By convention, links are defined at the end of the schema.

If the <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.

Attribute description

  • dstFilterExpr (string): this attribute lets you restrict the number of eligible values in the remote table.
  • xpath-dst (string): this attribute receives an Xpath (@name attribute of the remote table).
  • xpath-src (string): this attribute receives an Xpath (@name attribute in the current schema).