1

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

closed as too broad by Matthew Schmidt, Joël, carver, lungj, Nicolas Massart Aug 23 '17 at 18:29

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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

Not the answer you're looking for? Browse other questions tagged or ask your own question.