1

I need my smart contract to access data from some source. I want to build a smart Oracle in order to achieve this.

2

I think what you meant by "some source" is calling external APIs, like in order to query a database on the Internet.

Due to the deterministic nature of the EVM you need a service like Oracalize.

The Answers to following questions might help you as well : how can ethereum contract get data from a website, Why can't contracts make API calls

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