What are the database and architecture requirements for such an application?

Question

MySQL

Good day!
The task is to make a service for 10 stores, in which there will be all the goods of each store, more than 10 thousand. In it, they will be moderated, updated from price lists. A certain panel for managing your online stores. Stores will be added. Perhaps in the future a platform will be created and stores from opencart will switch to this system.
Question:
What kind of database architecture to create, for each site separate tables or a separate database for each store or hundreds of thousands of products in one to keep. Who worked with website builders, what kind of database they have for each client. And should I use mysql at all or should I consider another option? How would you build a database if there were 100 or more such stores.
It is a simple service for managers:
I chose a store, you see a list of goods, you can add, delete, update, click to add to the site. And yes, they will be added to the site via api or yml

Answer 1

What database architecture to create, for each site there are separate tables or a separate database for each store or hundreds of thousands of products in one to keep. Who worked with website builders, what kind of database they have for each client.

they have "such" base that will work this way and that way. depends on whether they sold support or not. the term "database architecture" has nothing to do with your question at all.
Again, this is not a technical question. development and maintenance cost. yes, even the ability to hire people for a project with one or another subd. I will tell you with 146% certainty that you can do it with mysql))
you are asking questions that do not have a clear answer in a purely technical plane.

Answer 2

Question:
What kind of database architecture to create, for each site separate tables or a separate database for each store or hundreds of thousands of products in one to keep. Who worked with website builders, what kind of database they have for each client. And should I use mysql at all or should I consider another option? How would you build a database if there were 100 or more such stores.

From the point of view of logic, security, common sense and a number of other factors, including architectural features (in terms of storing tables within the file system) of the databases themselves, I stored such data in different databases. But, taking into account the fact that "hundred thousand" lines is, by and large, "zilch" and the database of the "shared hosting" level (I think, not even VPS yet) - for convenience, you can store all this in one database.
As for whether it's worth using MySQL - personally for you, at the moment - I think it's worth it. Changing one database to another, without a full understanding of the context of why this is being done and how one differs from a durga - usually does not threaten anything good. The (popular) database engines themselves, "out of the box", do not differ too much from each other, and miraculously one of them "by default" will not be "better" than the other. I have repeatedly worked on projects where "hundreds of thousands" (records) appeared daily and they (these projects) felt great on MySQL'e.