set identity_insert <table> onそしてdbcc checkidentここにあなたの友達です。これは、私が過去に行ったことと似ています (コード サンプルを参照)。唯一の本当の注意点は、データを挿入できるのは更新プロセスだけであるということです。更新が進行している間、他のすべての人はプールから出なければなりません。もちろん、本番テーブルをロードする前に、この種のマッピングをプログラムで行うこともできます。ただし、挿入にも同じ制限が適用されます。更新プロセスは、実行される唯一のプロセスです。
--
-- start with a source schema -- doesn't actually need to be SQL tables
-- but from the standpoint of demonstration, it makes it easier
--
create table source.parent
(
id int not null primary key ,
data varchar(32) not null ,
)
create table source.child
(
id int not null primary key ,
data varchar(32) not null ,
parent_id int not null foreign key references source.parent(id) ,
)
--
-- On the receiving end, you need to create staging tables.
-- You'll notice that while there are primary keys defined,
-- there are no foreign key constraints. Depending on the
-- cleanliness of your data, you might even get rid of the
-- primary key definitions (though you'll need to add
-- some sort of processing to clean the data one way or
-- another, obviously).
--
-- and, depending context, these could even be temp tables
--
create table stage.parent
(
id int not null primary key ,
data varchar(32) not null ,
)
create table stage.child
(
id int not null primary key ,
data varchar(32) not null ,
parent_id int not null ,
)
--
-- and of course, the final destination tables already exist,
-- complete with identity properties, etc.
--
create table dbo.parent
(
id int not null identity(1,1) primary key ,
data varchar(32) not null ,
)
create table dbo.child
(
id int not null identity(1,1) primary key ,
data varchar(32) not null ,
parent_id int not null foreign key references dbo.parent(id) ,
)
-----------------------------------------------------------------------
-- so, you BCP or otherwise load your staging tables with the new data
-- frome the source tables. How this happens is left as an exercise for
-- the reader. We'll just assume that some sort of magic happens to
-- make it so. Don't forget to truncate the staging tables prior to
-- loading them with data.
-----------------------------------------------------------------------
-------------------------------------------------------------------------
-- Now we get to work to populate the production tables with the new data
--
-- First we need a map to let us create the new identity values.
-------------------------------------------------------------------------
drop table #parent_map
create table #parent_map
(
old_id int not null primary key nonclustered ,
offset int not null identity(1,1) unique clustered ,
new_id int null ,
)
create table #child_map
(
old_id int not null primary key nonclustered ,
offset int not null identity(1,1) unique clustered ,
new_id int null ,
)
insert #parent_map ( old_id ) select id from stage.parent
insert #child_map ( old_id ) select id from stage.child
-------------------------------------------------------------------------------
-- now that we've got the map, we can blast the data into the production tables
-------------------------------------------------------------------------------
--
-- compute the new ID values
--
update #parent_map set new_id = offset + ( select max(id) from dbo.parent )
--
-- blast it into the parent table, turning on identity_insert
--
set identity_insert dbo.parent on
insert dbo.parent (id,data)
select id = map.new_id ,
data = staging.data
from stage.parent staging
join #parent_map map on map.old_id = staging.id
set identity_insert dbo.parent off
--
-- reseed the identity properties high water mark
--
dbcc checkident dbo.parent , reseed
--
-- compute the new ID values
--
update #child_map set new_id = offset + ( select max(id) from dbo.child )
--
-- blast it into the child table, turning on identity_insert
--
set identity_insert dbo.child on
insert dbo.child ( id , data , parent_id )
select id = parent.new_id ,
data = staging.data ,
parent_id = parent.new_id
from stage.child staging
join #child_map map on map.old_id = staging.id
join #parent_map parent on parent.old_id = staging.parent_id
set identity_insert dbo.child off
--
-- reseed the identity properties high water mark
--
dbcc checkident dbo.child , reseed
------------------------------------
-- That's about all there is too it.
------------------------------------