Should UCS_BASIC character types have to look at collation elements when dealing with escape character in the LIKE clause?

• Key: DERBY-3315
• Type: Task
• Status: Resolved
• Resolution: Fixed
• Priority: Major
• Assignee: Mamta A. Satoor
• Reporter: Mamta A. Satoor
• Component/s: JDBC
• Affects Version/s: 10.3.1.4, 10.3.2.1, 10.4.1.3
• Fix Version/s: 10.3.3.0, 10.4.1.3

Description

Code in SQLChar.like(dvd, dvd) method at line number 1767 is executed for non-national/non-collation sensitive character types ie for UCS_BASIC character types and the code looks as follows
  // Make sure we fail for both varchar an nvarchar
  // for multiple collation characters.
  SQLChar escapeSQLChar = (SQLChar) escape;
  int[] escapeIntArray = escapeSQLChar.getIntArray();
  if (escapeIntArray != null && (escapeIntArray.length != 1))
  {
  throw StandardException.newException(SQLState.LANG_INVALID_ESCAPE_CHARACTER,new String (escapeSQLChar.getCharArray()));
   }

It appears that we are trying to see if number of collation elements associated with escape character is more than 1 and if yes, then we throw exception. Seems like a code like above should be done for collation sensitive character types and not for UCS_BASIC character types. Interestingly, nothing like this is getting checked for national character datatypes.

This behavior was detected while working on DERBY-3302