我有一个非常大的Oracle数据库,有很多表和数百万行数据。我需要删除其中一个表,但是希望确保删除不会破坏其他以其为外键的记录。有没有办法获取指向该表的所有其他记录或至少表架构的列表?我知道我可以自己尝试删除它并捕获异常,但我不能运行脚本并且需要第一次运行就成功。
我可以使用Oracle的SQL Developer和AllRoundAutomations的PL/SQL Developer工具。
提前感谢!
我有一个非常大的Oracle数据库,有很多表和数百万行数据。我需要删除其中一个表,但是希望确保删除不会破坏其他以其为外键的记录。有没有办法获取指向该表的所有其他记录或至少表架构的列表?我知道我可以自己尝试删除它并捕获异常,但我不能运行脚本并且需要第一次运行就成功。
我可以使用Oracle的SQL Developer和AllRoundAutomations的PL/SQL Developer工具。
提前感谢!
以下是我列出某个表的所有引用的解决方案:
select
src_cc.owner as src_owner,
src_cc.table_name as src_table,
src_cc.column_name as src_column,
dest_cc.owner as dest_owner,
dest_cc.table_name as dest_table,
dest_cc.column_name as dest_column,
c.constraint_name
from
all_constraints c
inner join all_cons_columns dest_cc on
c.r_constraint_name = dest_cc.constraint_name
and c.r_owner = dest_cc.owner
inner join all_cons_columns src_cc on
c.constraint_name = src_cc.constraint_name
and c.owner = src_cc.owner
where
c.constraint_type = 'R'
and dest_cc.owner = 'MY_TARGET_SCHEMA'
and dest_cc.table_name = 'MY_TARGET_TABLE'
--and dest_cc.column_name = 'MY_OPTIONNAL_TARGET_COLUMN'
;
使用这个解决方案,您还可以获得关于哪个表的哪个列正在引用目标表的哪个列的信息(并且您可以在此基础上进行筛选)。
/* The following query lists all relationships */
select
a.owner||'.'||a.table_name "Referenced Table"
,b.owner||'.'||b.table_name "Referenced by"
,b.constraint_name "Foreign Key"
from all_constraints a, all_constraints b
where
b.constraint_type = 'R'
and a.constraint_name = b.r_constraint_name
and b.table_name='XXXXXXXXXXXX' -- Table name
order by a.owner||'.'||a.table_name
最近我也遇到了类似的问题,但我很快发现仅查找直接依赖关系是不够的。因此,我编写了一个查询来显示多级外键依赖树:
SELECT LPAD(' ',4*(LEVEL-1)) || table1 || ' <-- ' || table2 tables, table2_fkey
FROM
(SELECT a.table_name table1, b.table_name table2, b.constraint_name table2_fkey
FROM user_constraints a, user_constraints b
WHERE a.constraint_type IN('P', 'U')
AND b.constraint_type = 'R'
AND a.constraint_name = b.r_constraint_name
AND a.table_name != b.table_name
AND b.table_name <> 'MYTABLE')
CONNECT BY PRIOR table2 = table1 AND LEVEL <= 5
START WITH table1 = 'MYTABLE';
它在我的数据库中,当将SHIPMENT用作MYTABLE时,会给出如下结果:SHIPMENT <-- ADDRESS
SHIPMENT <-- PACKING_LIST
PACKING_LIST <-- PACKING_LIST_DETAILS
PACKING_LIST <-- PACKING_UNIT
PACKING_UNIT <-- PACKING_LIST_ITEM
PACKING_LIST <-- PO_PACKING_LIST
...
SQL> declare
2 n pls_integer;
3 tot pls_integer := 0;
4 begin
5 for lrec in ( select table_name from user_constraints
6 where r_constraint_name = 'T23_PK' )
7 loop
8 execute immediate 'select count(*) from '||lrec.table_name
9 ||' where col2 = :1' into n using &&target_val;
10 if n = 0 then
11 dbms_output.put_line('No impact on '||lrec.table_name);
12 else
13 dbms_output.put_line('Uh oh! '||lrec.table_name||' has '||n||' hits!');
14 end if;
15 tot := tot + n;
16 end loop;
17 if tot = 0
18 then
19 delete from t23 where col2 = &&target_val;
20 dbms_output.put_line('row deleted!');
21 else
22 dbms_output.put_line('delete aborted!');
23 end if;
24 end;
25 /
Enter value for target_val: 6
No impact on T34
Uh oh! T42 has 2 hits!
No impact on T69
delete aborted!
PL/SQL procedure successfully completed.
SQL>
这个例子有点作弊。目标主键的名称是硬编码的,并且所有从属表上的引用列都具有相同的名称。修复这些问题留给读者做为练习 ;)
select c.owner, a.table_name, a.column_name, a.constraint_name,
c.r_owner as ref_owner, cpk.table_name as ref_table,
cpk.constraint_name as ref_pk
from all_cons_columns a
join all_constraints c on a.owner = c.owner
and a.constraint_name = c.constraint_name
join all_constraints cpk on c.r_owner = cpk.owner
and c.r_constraint_name = cpk.constraint_name
where c.constraint_type = 'r' and c.table_name= 'table_name';
我遇到了类似的情况。在我的情况下,我有几条记录,它们以大小写不同为唯一标识符。想要检查每个记录存在哪些依赖记录,以确定哪个更容易删除/更新。
以下代码会打印出指向给定记录的所有子记录,按每个子表格计算每个表格/主记录组合的数量。
declare
--
-- Finds and prints out how many children there are per table and value for each value of a given field
--
-- Name of the table to base the query on
cTable constant varchar2(20) := 'FOO';
-- Name of the column to base the query on
cCol constant varchar2(10) := 'ID';
-- Cursor to find interesting values (e.g. duplicates) in master table
cursor cVals is
select id
from foo f
where exists ( select 1 from foo f2
where upper(f.id) = upper(f2.id)
and f.rowid != f2.rowid );
-- Everything below here should just work
vNum number(18,0);
vSql varchar2(4000);
cOutColSize number(2,0) := 30;
cursor cReferencingTables is
select
consChild.table_name,
consChild.constraint_name,
colChild.column_name
from user_constraints consMast
inner join user_constraints consChild on consMast.constraint_name = consChild.r_constraint_name
inner join USER_CONS_COLUMNS colChild on consChild.CONSTRAINT_NAME = colChild.CONSTRAINT_NAME
inner join USER_CONS_COLUMNS colMast on colMast.CONSTRAINT_NAME = consMast.CONSTRAINT_NAME
where consChild.constraint_type = 'R'
and consMast.table_name = cTable
and colMast.column_name = cCol
order by consMast.table_name, consChild.table_name;
begin
dbms_output.put_line(
rpad('Table', cOutColSize) ||
rpad('Column', cOutColSize) ||
rpad('Value', cOutColSize) ||
rpad('Number', cOutColSize)
);
for rRef in cReferencingTables loop
for rVals in cVals loop
vSql := 'select count(1) from ' || rRef.table_name || ' where ' || rRef.column_name || ' = ''' || rVals.id || '''';
execute immediate vSql into vNum;
if vNum > 0 then
dbms_output.put_line(
rpad(rRef.table_name, cOutColSize) ||
rpad(rRef.column_name, cOutColSize) ||
rpad(rVals.id, cOutColSize) ||
rpad(vNum, cOutColSize) );
end if;
end loop;
end loop;
end;
SELECT referenced_table
,MAX(lvl) for_deleting
,MIN(lvl) for_inserting
FROM
( -- Hierarchy of dependencies
SELECT LEVEL lvl
,t.table_name referenced_table
,b.table_name referenced_by
FROM user_constraints A
JOIN user_constraints b
ON A.constraint_name = b.r_constraint_name
and b.constraint_type = 'R'
RIGHT JOIN user_tables t
ON t.table_name = A.table_name
START WITH b.table_name IS NULL
CONNECT BY b.table_name = PRIOR t.table_name
)
GROUP BY referenced_table
ORDER BY for_deleting, for_inserting;
Oracle约束使用表索引来引用数据。
要查找引用一个表的所有表,请按相反顺序查找索引。
/* Toggle ENABLED and DISABLE status for any referencing constraint: */
select 'ALTER TABLE '||b.owner||'.'||b.table_name||' '||
decode(b.status, 'ENABLED', 'DISABLE ', 'ENABLE ')||
'CONSTRAINT '||b.constraint_name||';'
from all_indexes a,
all_constraints b
where a.table_name='XXXXXXXXXXXX' -- Table name
and a.index_name = b.r_constraint_name;
注意:禁用引用可以显著提高DML命令(更新、删除和插入)的执行时间。
这对于批量操作非常有帮助,因为您知道所有数据都是一致的。
/* List which columns are referenced in each constraint */
select ' TABLE "'||b.owner||'.'||b.table_name||'"'||
'('||listagg (c.column_name, ',') within group (order by c.column_name)||')'||
' FK "'||b.constraint_name||'" -> '||a.table_name||
' INDEX "'||a.index_name||'"'
"REFERENCES"
from all_indexes a,
all_constraints b,
all_cons_columns c
where rtrim(a.table_name) like 'XXXXXXXXXXXX' -- Table name
and a.index_name = b.r_constraint_name
and c.constraint_name = b.constraint_name
group by b.owner, b.table_name, b.constraint_name, a.table_name, a.index_name
order by 1;