[OLINGO-1447] select visitor needed for many cases

• Type: Improvement
• Status: Open
• Priority: Critical
• Resolution: Unresolved
• Affects Version/s: (Java) V4 4.7.1
• Component/s: odata4-server
• Assignee: Unassigned
• Reporter: Werner Daehn
• Created: 17/Apr/20 07:23
• Updated: 17/Apr/20 07:43

Description

The oData entity might return more columns that the database table o read from actually contains. Therefor it would be good to have a visitor pattern for the select list as well, similar to the $filter implementation.

 

Example: My table has the columns FIRSTNAME, LASTNAME. The oData service should have another extra column FULLNAME which is the concat of the two. 

Using the suggested code line

String selectList = odata.createUriHelper().buildContextURLSelectList(edmEntityType, null, selectOption);

returns all three columns and the SQL will fail. The SQL to be generated needs to be 

select FIRSTNAME, LASTNAME, FIRSTNAME || ' ' || LASTNAME from ...

 

I would think this is a quite common requirement, e.g. the ID column of a table with multiple PK columns would be the concat of all.

 

Actually, thinking about it, it needs to be more than that. The same artificial column can be used in a filter as well.

 

Any ideas?