是否可以通过脚本/工具使用 Oracle PL/SQL 基于表 fk 关系自动生成许多删除语句?
在示例中:我有表:CHICKEN (CHICKEN_CODE NUMBER) 并且有 30 个表对其 CHICKEN_CODE 的 fk 引用,我需要删除;还有其他 150 个表外键链接到我需要先删除的 30 个表。
是否有一些我可以运行的工具/脚本 PL/SQL,以便根据 FK 关系为我生成所有必要的删除语句?
(顺便说一句,我知道关系上的级联删除,但请注意:我不能在我的生产数据库中使用它,因为它很危险!)
我正在使用 Oracle 数据库 10G R2。
请注意这一点:
Generate Delete Statement From Foreign Key Relationships in SQL 2008?
另一个用户刚刚在 SQL SERVER 2008 中编写它,任何人都可以转换为 Oracle 10G PL/SQL?
我不能... :-(
请假设 V_CHICKEN 和 V_NATION 是从根表中选择要删除的 CHICKEN 的条件:条件是:根表上的“其中 COD_CHICKEN = V_CHICKEN AND COD_NATION = V_NATION”。
最佳答案
(我的第一个答案变得太长且难以编辑,并且得到了社区维基化,这真的很烦人。这是脚本的最新版本。)
此脚本尝试通过递归执行级联删除。当存在循环引用时,应避免无限循环。但它要求所有循环引用约束都具有 ON DELETE SET NULL
或 ON DELETE CASCADE
.
CREATE OR REPLACE PROCEDURE delete_cascade(
table_owner VARCHAR2,
parent_table VARCHAR2,
where_clause VARCHAR2
) IS
/* Example call: execute delete_cascade('MY_SCHEMA', 'MY_MASTER', 'where ID=1'); */
child_cons VARCHAR2(30);
parent_cons VARCHAR2(30);
child_table VARCHAR2(30);
child_cols VARCHAR(500);
parent_cols VARCHAR(500);
delete_command VARCHAR(10000);
new_where_clause VARCHAR2(10000);
/* gets the foreign key constraints on other tables which depend on columns in parent_table */
CURSOR cons_cursor IS
SELECT owner, constraint_name, r_constraint_name, table_name, delete_rule
FROM all_constraints
WHERE constraint_type = 'R'
AND delete_rule = 'NO ACTION'
AND r_constraint_name IN (SELECT constraint_name
FROM all_constraints
WHERE constraint_type IN ('P', 'U')
AND table_name = parent_table
AND owner = table_owner)
AND NOT table_name = parent_table; -- ignore self-referencing constraints
/* for the current constraint, gets the child columns and corresponding parent columns */
CURSOR columns_cursor IS
SELECT cc1.column_name AS child_col, cc2.column_name AS parent_col
FROM all_cons_columns cc1, all_cons_columns cc2
WHERE cc1.constraint_name = child_cons
AND cc1.table_name = child_table
AND cc2.constraint_name = parent_cons
AND cc1.position = cc2.position
ORDER BY cc1.position;
BEGIN
/* loops through all the constraints which refer back to parent_table */
FOR cons IN cons_cursor LOOP
child_cons := cons.constraint_name;
parent_cons := cons.r_constraint_name;
child_table := cons.table_name;
child_cols := '';
parent_cols := '';
/* loops through the child/parent column pairs, building the column lists of the DELETE statement */
FOR cols IN columns_cursor LOOP
IF child_cols IS NULL THEN
child_cols := cols.child_col;
ELSE
child_cols := child_cols || ', ' || cols.child_col;
END IF;
IF parent_cols IS NULL THEN
parent_cols := cols.parent_col;
ELSE
parent_cols := parent_cols || ', ' || cols.parent_col;
END IF;
END LOOP;
/* construct the WHERE clause of the delete statement, including a subquery to get the related parent rows */
new_where_clause :=
'where (' || child_cols || ') in (select ' || parent_cols || ' from ' || table_owner || '.' || parent_table ||
' ' || where_clause || ')';
delete_cascade(cons.owner, child_table, new_where_clause);
END LOOP;
/* construct the delete statement for the current table */
delete_command := 'delete from ' || table_owner || '.' || parent_table || ' ' || where_clause;
-- this just prints the delete command
DBMS_OUTPUT.put_line(delete_command || ';');
-- uncomment if you want to actually execute it:
--EXECUTE IMMEDIATE delete_command;
-- remember to issue a COMMIT (not included here, for safety)
END;
关于oracle - 如何根据表 FK 关系在 PL/SQL 中生成 DELETE 语句?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/2677081/