如何按依赖顺序列出表（基于外键）？

Question

这个问题最初是由@PrateekGupta 提出的

背景

@PrateekGupta 想对多个 table 执行批量插入操作。
table 之间有外键关系。
如果在插入引用的 table 之前使用外键对 table 执行 INSERT 操作，则操作可能会因违反外键而失败。

要求

根据依赖关系在数据库中生成 table 的列表。
没有依赖项（没有外键）的表将排在第一位。
仅在第一组 table 中具有依赖关系的表将排在第二位。
仅在第 1 组或第 2 组 table 中具有依赖关系的表将排在第 3 位。
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

WITH cte (lvl, object_id, name, schema_Name) AS
  (SELECT 1, object_id, sys.tables.name, sys.schemas.name as schema_Name
   FROM sys.tables Inner Join sys.schemas on sys.tables.schema_id = sys.schemas.schema_id
   WHERE type_desc = 'USER_TABLE'
     AND is_ms_shipped = 0
   UNION ALL SELECT cte.lvl + 1, t.object_id, t.name, S.name as schema_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 )
   JOIN sys.schemas as S on t.schema_id = S.schema_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 schema_Name, name, MAX (lvl) AS dependency_level
FROM cte
GROUP BY schema_Name, name
ORDER BY dependency_level,schema_Name, name;

Answer 3

我需要自己做这件事，希望有人已经为 Postgres 做过，但没有找到任何东西，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。如果您需要查看外键指向哪个 table，您可以删除 GROUP BY 和 SELECT source::regclass。

Answer 4

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 5

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

可以在这里看到标志选项

EXEC sp_msdependencies '?'

遗憾的是，SQLAzure 不提供此功能。

如何按依赖顺序列出表（基于外键）？

How to list tables in their dependency order (based on foreign keys)?

sql-server

foreign-keys

database-metadata

背景

要求