In this version : * EXISTS * consistency check in INSERT...SELECT * DISTINCT, ALL * transactions The transaction stuff is pellicular. It simply maps to vendor calls. I am hesitating a bit, either make a common interface for the most common operations (like execute) directly in each backend (aside with vendor-specifc calls) or put them in a separate wrapper or even decide that it's not in the scope. There's more redesign in the select from which I think I can get an elegant implementation of vendor-specific features (like LIMIT). The idea is to pass all the data in a fusion map, allowing vendor specific parts of the statement to slip their own data inside it. In fact this also is how DISTINCT works. I dropped the composition of lists via chained calls to operator (). It's all preprocessor-based now. The () chain system was limited by FUSION_MAX_VECTOR_SIZE anyway. I have installed MySQL on my computer. I am still accessing it via ODBC but I'll probably start the native support soon. Yesterday I tried to upload and just when I pushed the upload button the vault server crashed. I suspect that it was my upload that triggered it. J-L