將CHAR替換爲VARCHAR2

Question

如何在模式中的所有表中將CHAR替換爲VARCHAR2？

注意：我滿足於返回ALTER TABLE語句的查詢，因此我可以保存該腳本並再次運行它。

Answer 1

select 'ALTER TABLE "' || owner || '"."' || table_name 
|| '" MODIFY ("' || column_name 
|| '" VARCHAR2(' || data_length || '));' 
from all_tab_columns tc 
where data_type = 'CHAR' 
and owner = :schemaname 
and exists (
    select 1 
    from all_tables t 
    where tc.owner = t.owner 
    and tc.table_name = t.table_name 
);