级联主键更新到oracle中所有引用外键

Question

更新主键时是否可以更新Oracle中所有引用的外键？

像这样的过程，获取表名和主键，查找所有表中的所有外键，并使用新值更新它

  PROCEDURE cascade_update_primary(
                          table_name IN VARCHAR2,
                          primary_column IN Number,
                          new_value IN Number);

甲骨文不支持ON UPDATE CASCADE。

Answer 1

具有DEFERRABLE外键约束：

create or replace procedure cascade_update_primary
(
  p_table_name in varchar2,
  p_old_value in number,
  p_new_value in number
)
as
  l_column_name varchar2(128 char);
begin
  select
    cc.column_name into l_column_name
  from
    user_cons_columns cc
    join user_constraints c on (c.constraint_name = cc.constraint_name)
  where
    c.constraint_type = 'P' and c.table_name = p_table_name
  ;

  execute immediate 'set constraints all deferred';

  execute immediate 'update "' || p_table_name || '" set "' || l_column_name || 
    '" = :B1 where "' || l_column_name || '" = :B2' using p_new_value, p_old_value;

  for c in (
    select
      cc2.table_name, cc2.column_name
    from
      user_cons_columns cc
      join user_constraints c on (c.constraint_name = cc.constraint_name)
      join user_constraints c2 on (c.constraint_name = c2.r_constraint_name)
      join user_cons_columns cc2 on (c2.constraint_name = cc2.constraint_name)
    where
      c.constraint_type = 'P' and c.table_name = p_table_name
      and cc.column_name = l_column_name
  )
  loop
    execute immediate 'update "' || c.table_name || '" set "' || c.column_name || 
      '" = :B1 where "' || l_column_name || '" = :B2' using p_new_value, p_old_value;
  end loop;
end;
/

对于NOT DEFERRABLE外键，进行一些修改：

1. 插入具有新 PK 值的父行
2. 将子表更新为新值
3. 删除具有旧 PK 值的父行