Question

这个问题最初是由@PrateekGupta提出的

背景

@PrateekGupta想要对多个表执行批量插入操作表格之间有外键关系如果在插入引用的表之前对具有外键的表执行INSERT操作，则操作可能会因违反外键而失败。

Reuierment

根据数据库的依赖关系生成数据库中的表列表没有依赖关系的表（没有外键）将是第1个仅在第1组表中具有依赖关系的表将是第2个仅在第1或第2组表中具有依赖关系的表将是第3个等等...

Answer 1

    example:

    create table t1 (i int primary key,j int unique)
    create table t2 (i int primary key references t1 (i));
    create table t3 (i int,j int,primary key (i,j));
    create table t4 (i int,j int,  foreign key (i,j) references t3 (i,j));
    create table t5 (i int references t1 (i),j int,foreign key (i,j) references t3 (i,j));
    create table t6 (i int references t2 (i));

with        cte (lvl,object_id,name)
            as 
            (
                select      1
                           ,object_id
                           ,name

                from        sys.tables

                where       type_desc       = 'USER_TABLE'
                        and is_ms_shipped   = 0

                union all

                select      cte.lvl + 1
                           ,t.object_id
                           ,t.name
                from                    cte

                            join        sys.tables  as t

                            on          exists
                                        (
                                            select      null

                                            from        sys.foreign_keys    as fk

                                            where       fk.parent_object_id     = t.object_id 
                                                    and fk.referenced_object_id = cte.object_id
                                        )

                                    and t.object_id <> cte.object_id
                                    and cte.lvl < 30

                where       t.type_desc     = 'USER_TABLE'      
                        and t.is_ms_shipped = 0
            )


select      name
           ,max (lvl)   as dependency_level

from        cte

group by    name

order by    dependency_level
           ,name
;

Answer 2

感谢大卫。

如果有人需要，我刚刚将架构名称添加到他的查询中

GetXML

Answer 3

脚本的Oracle版本：

with 
    foreign_keys as (
        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 = :owner),
    cte (lvl,table_name) as (
        select 1, table_name
        from all_tables
        where 
            owner = :owner
        union all
        select cte.lvl + 1, t.table_name
        from cte
        join all_tables t on exists (
            select null 
            from foreign_keys fk 
            where 
                fk.src_table = t.table_name
                and fk.dest_table = cte.table_name
        )
        and t.table_name <> cte.table_name
            AND cte.lvl < 30
    )
select table_name, max (lvl)   as dependency_level
from        cte
group by    table_name
order by    dependency_level desc, table_name
;

Answer 4

以上答案不适用于循环引用。您可以改用此存储过程。

EXEC sp_msdependencies @flags = 8

可以在此处查看标志选项

EXEC sp_msdependencies '?'

不幸的是，这在SQL Azure上不可用。

Answer 5

我需要自己做这件事，希望有人已经为Postgres做过，但是什么也没找到，所以我就把它留在这里：

WITH RECURSIVE t AS (
    SELECT relnamespace as nsp, oid as tbl, null::regclass as source, 1 as level
    FROM pg_class
    WHERE relkind = 'r'
        AND relnamespace not in ('pg_catalog'::regnamespace, 'information_schema'::regnamespace)
UNION ALL
    SELECT c.connamespace as nsp, c.conrelid as tbl, c.confrelid as source, p.level + 1
    FROM pg_constraint c
    INNER JOIN t p ON (c.confrelid = p.tbl AND c.connamespace = p.nsp)
    WHERE c.contype = 'f'
        AND c.connamespace not in ('pg_catalog'::regnamespace, 'information_schema'::regnamespace)
)
SELECT nsp::regnamespace, tbl::regclass
FROM t
GROUP BY nsp, tbl
ORDER BY max(level) DESC;

这是两个用例之间的混合查询。如果需要查看外键引用到哪个表，则可以改为删除GROUP BY和SELECT source::regclass。

如何按依赖顺序列出表（基于外键）？

背景

Reuierment

5 个答案: