We dont want to tell the current vendor we will replace their system with a new one. But I want to ask them for a complete SQL Dump.
I need some advice on asking that information in a polite way.
If you anticipate winning more customers from this vendor, you write that script to be re-usable in the future. And you write another one each time you displace a competitive vendor.
Eventually, you have a library of scripts and can start marketing how smoothly and quickly you can migrate new customers off those vendors.
Also, I'm afraid they may send me the data incomplete without important relational keys between tables.
And yes, your fears are justified. They certainly will send you something that will make the task have challenges. There is always reverse engineering to be done. But that doesn't change what you need to do.
You just need to have an expectation that data migrations are work. If you do this enough, you'll get crazy stuff, not just SQL dumps. I've frequently receive CSVs, Excel files, Word documents. I've even gotten PDF and had to OCR them to get the data. I've gotten proprietary data formats that forced me to track down database that aren't sold anymore, or go through painful purchasing processes to buy and install obscure databases just to get the data up and running locally and then dump it to something usable.
But at the end of it all, responsibilities are fairly clear:
- The customer has to ask for the data.
- The vendor needs to provide it, but doesn't need to make it friendly.
- You need to take on the burden of making it usable.