How can I replicate many to many relationship

Question

I have a product database where I am trying to replicate a particular product's data and relationships to a new product, a clone. I am puzzled however on how to replicate several many to many relationships. For example, consider a product with two parts, and for each part, their are several colors available. I have a Product table, a product Areas table, and a Colors table. The product id is a foreign key in the area table, one to many. The Area table has an area id (pk) along with other descriptive fields, and the Colors have color ids (pk) along with palette information. A fourth table serves as the many to many look up table, it's primary key being the part id and the color id combined. This is a pretty straight forward configuration as far as it goes.

I can't think of a way to clone this structure, however, despite many approaches which would be way too much to elaborate upon here. I can easily enough replicate the left hand, product-area relationship, generating new AreaIDs (A,B,C). But in a next step, I then want to replicate the many-to-many relationship using the new area ids. However, now I don't know which original ID (H,L,W) to associate with which new ID. For example, does the new id A get mapped to the set of colors from the old ID H, L, or W? I have only id's to work with. I can select both parts and part-color pairs from the source in one select statement, but I can't insert into two tables with one statement.

In other words, how do I replicate many to many relationships if I want to supply a new ID for half of it? Do I have to resort to cursors? I can if I need to, but I'm imagining there an elegant way to accomplish this that I just can't figure out. Maybe using a temp table or some sort of table valued function? I've tried to search for answers, but I all I can find is advice on setting up many-to-many relationships.

Thanks for you experts who have the patience to read through this question.

James

Answer 1

SymmetricDS replicates tables that have many into many relationships using change data capture. The key is to perform an initial load to get the databases in sync initially so that if a child record is updated the change data capture will also work. In the latest versions of SymmetricDS (3.10 and higher) it will also auto resolve foreign key errors if the databases are not in sync. If a child row is being loaded to a target without the parent it will callback to the source to load the missing parent as well so that you do not need to intervene.