Oracle Magazine, Nov/Dec 2017
Database Developer and DBA ETL NAME column to find rows efficiently All looks as it should until when a subsequent query is being run the realization that there might be an underlying issue ORACLE MAGAZINE NOVEMBER DECEMBER 2017 78 SQL select 2 from customers 3 where upper cust_ name ADAMS COUNTRY CREATED CUST_ NAME AUS 07 NOV 16 Adams AUS 08 NOV 16 ADAMS AUS 09 NOV 16 adams This second query suggests a possible flaw in application logic with respect to the database design Due to the way the application has been coded its possible that incomplete results are being returned to the consumers of that first query because the rows with the surname ADAMS in mixed case are being dropped If case insensitivity is indeed the desired goal for this application a potentially large refactoring exercise is going to be required because the application code will need to be revisited to recast any SQL statements with the predicate CUST_ NAME value to include the UPPER expression applied to the CUST_ NAME column UNINTENDED SIDE EFFECTS Not only do the two queries to the CUSTOMER table return different results but they also have differing performance characteristics as you can see in the execution plans for each
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