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Bronze Tier:
The purpose for bronze tier is to store data downloaded from external world into data lake so we can use all sort of tools inside data lake to further process it
- raw data
- no uniformed format, could be csv, JSON, AVRO, parquet, binary, anything
- could even be unstructured
- no data quality assurance
Silver Tier:
The purpose for bronze tier is to allow data ingestion application to sanitize data, verify the quality of the data
- Data quality is assurred
- Data may not be normalized. One table may use UTC for a timestamp column while aother table may use timestamp without timezone. No stadnardlization for column name.
- Data format is uniformed, usually it is stored as a format that is best fits the further ETL process, for example parquet.
Gold Tier:
Tables for star schema
- dimention tables and fact tables that forms star schema
Platinum Tier:
Various query result for specific business questions materized in tables
- Various query result for specific business questions materized in tables
- Tables may be replicated to a RDBMS for BI tool to access (sometime you can expose them directly, e.g. Spark Thrift Server)
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