Comment by ezst
14 hours ago
> entities are fundamentally different from tables
Isn't the fact that they are _mostly_ interchangeable the foundational principle of hundreds of ORMs? Of course the DDL doesn't say much about the entity's lifecycle, but if the bar is set at representing its relationships, fields and cardinality as a graph, it seems sufficient?
I think most successful ORMs have an additional layer of semantics beyond what can be directly expressed in SQL. For example, Active Record has multiple types of associations (belongs_to, has_one, has_many, etc.) that I would argue align more closely to the ER model than the relational model. Of course you can come up with a set of conventions to go from ER to relational when everything is fed through the ORM, but you are losing some semantic information in the process. (That is, if you just look at the SQL table definitions, you don't have the same information about relationships).
ORMs are on a poor foundation. But I don't see the problem with this tool, it's just showing the tables.
I don't see a problem with the tool either really, it's just a pet peeve of mine to call what it produces an ER diagram when it's really a diagram of the relational model defined by the SQL.