Public API for datapackage <> sql metadata conversion

[ezwelty]

Overview

Say you have a frictionless.Package and want the equivalent SQL metadata (as sqlalchemy.Metadata). Maybe you want to generate the SQL commands that would generate the database using sqlalchemy.schema.CreateTable. Here is how this can be currently accomplished:

import frictionless

def package_to_sql(package, db):
  storage = frictionless.plugins.sql.SqlStorage(db)
  for resource in package.resources:
    _ = storage._SqlStorage__write_convert_schema(resource)
  return storage._SqlStorage__metadata

So although the conversions already exist within frictionless.plugins.sql, accessing them has two major downsides: the methods are private and they require an active database connection, even though only the sql dialect is needed (e.g. 'mysql', 'postgresql', etc).

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Please preserve this line to notify @roll (lead of this repository)

[roll]

@ezwelty Good idea. We can extract this as a static helper

[ezwelty]

@roll I could work on this if you'd like. Would you want these as @staticmethod of SqlStorage, helper functions directly in the plugins.sql module, or elsewhere ?

[roll]

It's great @ezwelty,

I think we can have a high-level package.to_sql_metadata in the Package class and on the plugin level, a static method is a good idea in my opinion.

I'm assigning you to show that's in work :+1:

[roll]

PARTIALLY IMPLEMENTED the follow-ups - https://github.com/frictionlessdata/framework/issues/1365