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ORA-43929: Collation cannot be specified if parameter MAX_STRING_SIZE=STANDARD is set

The default collation can only be set if the init parameter max_string_size is set to extended.

SQL> select value from v$parameter where name = 'max_string_size';
STANDARD

SQL> alter session set default_collation = using_nls_comp;
ORA-43929: Collation cannot be specified if parameter MAX_STRING_SIZE=STANDARD is set

ORA-43929: Collation cannot be specified if parameter MAX_STRING_SIZE=STANDARD is set

See also