Data science is the extraction of knowledge from data, which is a continuation of the field data mining and predictive analysis. Data science is related to data mining and big data.
Big data is a broad term for data sets so large or complex that traditional data processing applications are inadequate. Big data is a field that treats ways to analyse, systematticaly extract information from, or otherwise deal with data sets that are too large or complex to be dealt with by traditional data processing application software.