Since indexes are basically created in the same type as the table, indexes of disk tables cannot be created in the memory tablespace, and an ERR-311EC error is displayed.
iSQL> create table t1 (c1 char(10), c2 char(5)) tablespace SYS_TBS_DISK_DATA;
If the user tries to create a disk table index in the memory tablespace (SYS_TBS_MEM_DATA) as shown below, an ERR-311EC error occurs.
iSQL> create index idx_t1 on t1(c1 desc) tablespace SYS_TBS_MEM_DATA;
If the index of the disk table is created in the disk tablespace, it is created normally without causing an error.
Create disk table index in disk tablespace
iSQL> create index idx_t1 on t1(c1 desc) tablespace SYS_TBS_DISK_DATA;