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In the DataAccess:SourceColumn use the appropriate DATA-SOURCE (that static one or the dynamic one). As the fields from the additional DATA-SOURCE buffers are typically not mapped to temp-table fields, cusotm code is required to return the appropriate database table field name for a temp-table field (e.g. a calculated field that contains a description text) that may occur in the query string or query sort. This article provides a simple example of this: Filtering in a Data Access class on a table that is not part of the (default) data-source.
In the DataAccess:SourceDefaultQuery you’ll have to return the default query that fits for the current use case. Similar to what you need to do in AttachDataSources you’ll have to consider the current case. In many cases you can return the standard query string generated by the Business Entity Designer. But when the dynamic data-source handle is valid and it’s a read operation you may return “FOR EACH SalesRep, EACH Customer OF SalesRep”.
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