ETL and ELT

Defining the ETL Process

1. Extract data from an external source into a data lake

   • These external sources could include:

     • Operational systems
     • Third party APIs
     • RDBMS
     • etc.

2. Next, transform that data from the data lake

   • Transformation tools include:

     • Sqoop
     • HQL
     • etc.

3. Then, load the transformed data either:

   • Back into the data lake
   • Or into a data warehouse

Defining the ELT Process

1. Extract data from an external source into a data lake

   • These external sources could include:

     • Operational systems
     • Third party APIs
     • RDBMS
     • etc.
2. Next, load the data from the data lake into a data warehouse

3. Then, transform the data in the data warehouse

   • Afterwards, we can load it back into the data warehouse

References

• Defining ETL Transformations
• Comparing ETL and ELT Tools