Copy parent/child rows to same respective tables

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Copy parent/child rows to same respective tables

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Topic

PHead1223
Starting Member

1 Post

Posted - 2008-02-29 : 17:04:35

My Question: Does anyone know of a decent way (i.e. I do not want to loop to insert each row and check the SCOPE_IDENTITY() field or anything like that) to copy parent/child rows to their same respective table besides using the method I have listed below (my manager does not really like the idea of the "PreviousID" field)? More details are listed below.

My Table Situation: I have a parent table and a child table. Both tables have an identity column as the primary key. The relationship between the tables is established using the parent table's primary key to the column in the child table that stores the relationship. The identity column in both tables is the only column that is unique in the tables.

Sample Data (made up and simplified for visualization purposes):
ParentTable - "Items"
ID ItemCategory Price
1,T-Shirt,$20
2,Blue Jeans,$50
3,T-Shirt,$40

ChildTable - "Components
ID ItemID Component
1,1,Fabric
2,1,ScreenPrinting
3,2,Fabric
4,2,Zipper
5,3,ThickFabric
6,3,ScreenPrinting
7,3,Elastic

My Need: I need to make a copy of the records (keeping the parent/child relationship intact) to the same table as the source records. For example, in my data example above, I may need to make a copy of all the "T-Shirt" items and their child records. As the parent records are copied, they will be assigned new keys since the primary key is an identity. Obviously, this new key needs to be used when creating the child records, but I need to somehow associate this new key to the new child records.

Possible Solution: I know this can be achieved by adding another column to the parent table to store the "PreviousID" (INT NULL). Using this new field, when I want to copy the "T-Shirt" items, I would insert the new records and store the ID of source records (i.e. the identity value of the row that was copioed would be stored in this "PreviousID" field). Once the parent record has been copied, I could then insert the child records, and I could join on the "PreviousID" field to get to the new ID to use for inserting the copies of the child records.

Thanks for reading this and for any help offered.

dataguru1971
Master Smack Fu Yak Hacker

1464 Posts

Posted - 2008-02-29 : 20:55:17

Can't you set up triggers for On Update and such that handle the required referential integrity (Foreign keys are necessary for this...)

Poor planning on your part does not constitute an emergency on my part.

PeterNeo
Constraint Violating Yak Guru

357 Posts

Posted - 2008-03-01 : 01:39:32

can u post some sample output u r expecting for the given input info.

try using OUTPUT clause when inserting into parent table.

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