fix: LOB failures during OnConflict merges

[joboon]

Description

One-to-one or one-to-many relationships which have LOB types in the child table fail when the size of the LOB exceeds 32767 characters (the max length for VARCHAR2). The merge statement assigns a bind variable which is typed as just a string or []byte. The fix converts the string or []byte bind variable to a godror.Lob object when its size exceeds MaxInt16.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

I have added two new tests which produce this behavior and validate the fixes. You can uncomment the fixes in common.go to see the original failure.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[ting-lan-wang]

Thank you for submitting the fix!
The changes look good to me.