db-importer refactoring sketch

example.js

//mysql.js
const getConnection = () => foo();
const importTables = () => bar();
const getConstraints = () => xyz();
module.exports = {getConnection, importTables, getConstraints};

//sqlite.js : idem
const getConnection = () => fizz();
const importTables = () => qux();
const getConstraints = () => arg();
module.exports = {getConnection, importTables, getConstraints};

//etc...

//index.js
const dbms = () => somethingSomething; // return the appropriate module
const connection = dbms().getConnection();
const tables = dbms().importTables();