On my todo list, I found a topic which I wanted to blog about for a long time. The problem is how to create a ViewObject, based on EntityObjects, which builds a full outer join between two tables.
For those of you who don’t know about full outer joins in SQL here is a short description from https://www.w3schools.com/sql/sql_join_full.asp:
The FULL OUTER JOIN keyword return all records when there is a match in either left (table1) or right (table2) table records.
Note: FULL OUTER JOIN can potentially return very large result-sets!
FULL OUTER JOIN Syntax:
FULL OUTER JOIN table2 ON table1.column_name = table2.column_name;
There are not too many use cases where you need to use a full outer join, but they exist (e.g. https://searchoracle.techtarget.com/answer/Another-good-FULL-OUTER-JOIN-example or to compare two or more tables).
Problem: How can a full outer join be created in ADFbc?
I show how to create a VO based on Employees and Department EO using a full outer join on the department_id. This VO will return all departments with all their employees, departments which don’t have any employee and all employees who don’t have a department. Read the complete article here.
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