I've been teaching myself SSDT for use on an upcoming project that I expect to be working on. My understanding of the "publish" operation is that it will take my SQL Server Data Project code, use that to generate something like a reference database, and then use that to compare against my target-deploy database, figure out what changes are required to get the schema into line with the reference db, and then make them.
But for a table rename, this did not happen, and I'm hoping somebody can explain what is wrong with my mental model of the process.
I've got a very simple "library" themed test database with tables like "Libraries", "Books", and "Categories". All very simple 2-3 columns just to experiment with. Then I added a 4th table "Books_MM_Categories" to represent a many-to-many link table between "Books" and "Categories".
I published that, and all was as expected. But, I'd deliberately named the link table 'wrong' to that I could try renaming it. So I renamed the sql file in my DB project, and changed its code to instead create a table named "Books_Categories_Link".
This time when I published, I expected the "Books_MM_Categories" table to be deleted from the DB, and the new one added... or to have some kind of sp_rename procedure show up to rename the table.
Instead, what I got was that both tables are now present. I can understand that my sloppy rename would have lost all the data, simply just causing one new table to be created, and the old one dropped, instead of ACTUALLY renamed... But what I can't figure out is why the original table is not dropped. In my mental model of how this works, a table/column/view/sproc that no longer exists in the reference should be likewise eliminated from the published database. If not, then I should expect to see some error messages telling me it chose not to drop the table because of anticipated dataloss.
I did see a couple of post explaining how to use the "refactor" option in the code view window... That is working as I would expect. So I understand how to do it properly going forward.
Can anybody explain whats wrong with my mental model of how this works? I'm sure its working as it is supposed to, but I'd like to understand where I went wrong. Why does a table not listed in my project not get deleted on publish (I've not tried it but expect the same exact behavior if I export a .dacpac first and then use that to perform the deployment of the new scheme.
Thanks
EDIT 1
Somewhat curiously, when running a "Schema Compare" operation, the extra table is detected and flagged for deletion.