包括但不能删除SQL架构比较

Question

I am attempting to use SQL Schema Compare in Visual Studio 2013/15 and am running into the problem that discluding tables from delete removes them from being processed at all.

The issue is that the tables it is trying to delete are customer made tables, so when we sync our version against their databases it asks to delete them. We do not want to delete them, but some of their tables have constraints on ours so when it attempts to CCDR it fails due to table constraints. Is there a way to add the table to be (re-created? like the rest of them?), without writing scripts for each client to do what SQL Schema Compare already does just for those few tables?

Red-Gate's SQL Compare does this somehow, but it's hidden from us so not quite sure how it's achieved. Discluding doesn't delete, but does not error on the script either.

UPDATE:

The option "Drop constraints not in source" does not appear to work correctly. It does drop some, however there are others that it just does not drop the constraints. In red-gate's tool, when we compared I found how to get the SQL from it, and their product doesn't say the table needs to be updated at all, while Visual Studio's does. They seem to work almost identical, but the tables that fail are the ones that shouldn't be update at all (read below)

Update 2:

Another problem I've found is "Ignore column collation" also doesn't work correctly, as tables that shouldn't be getting dropped are being told they need to be updated even though it's only order of column changes, not actual column or data changes, which makes this feel like more of a bug report than anything.

Answer 1

My suggestion with these types of advance data calculations is to not use Visual Studio. Put the logic on the Sql engine and write the code for this in Sql. Due to the multi user locking issues of a Sql engine these types of processes are prone to fail when the wrong combinations of user actions happen at the same time. The Visual Studio tool can not interface with the data locking issues due to records changing that the Sql engine can. If you even get this to work it will only be safe to run if you are in single user mode.

It is a nice to use tool, easier than writing Sql but there are huge reliability and consistency risks for going down this path.

Answer 2

I don't know if this will help but I've found this paragraph on the following page: https://msdn.microsoft.com/en-us/library/hh272690(v=vs.103).aspx

The update will fail because our change involves changing a column from NOT NULL to NULL and as a result causes data loss. If you want to proceed with the update, click on the Options button (the fifth one from the left) on the toolbar for the Schema Compare and uncheck the block incremental deployment if data loss option.