Oracle : Ошибка ORA-22857

"cannot modify columns of object tables"
*Cause: An attempt was made to alter the object table by modifing
existing columns. An object table cannot be altered to modify
existing columns since it is based on an object type. The table
definition must be in sync with the corresponding type.
*Action: Create a new type with the desired attribute types and use it
to create an object table. The new object table will have the
desired columns.

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