You can use oledb provider for connect mysql database. Few mysql dataprovider also exists for connect mysql datababase. Please visit following links for mysql data providers.
mysql data providers
Now if you want to use multiple database simultaneously then your dataaccess/repository layer should be ready for that. You can use factory design pattern when will be responsible for provide db connection object based on your parameter. You can use that connection in your dal/repository layer for communicate with database.
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