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Difference between ETL and ELT Pipelines

ETL (Extract, Transform, Load) and ELT (Extract, Load, Transform) are two common architectures for data pipelines. Both involve extracting data from one or more sources, loading the data into a destination system, and possibly transforming the data in some way. The main difference between the two approaches is the order in which the transform and load steps are performed.


In an ETL pipeline, the transform step is typically performed before the data is loaded into the destination system. This means that the data is cleaned, transformed, and structured into a form that is optimized for the destination system before it is loaded. The advantage of this approach is that it can be more efficient, since the data is transformed once and then loaded into the destination system, rather than being transformed multiple times as it is queried. However, ETL pipelines can be inflexible, since the data must be transformed in a specific way before it is loaded, and it can be difficult to modify the pipeline if the data requirements change.


In an ELT pipeline, the load step is performed before the transform step. This means that the data is loaded into the destination system in its raw, unstructured form, and then transformed and cleaned as needed. The advantage of this approach is that it is more flexible, since the data can be transformed in any way that is required, and it is easier to modify the pipeline if the data requirements change. However, ELT pipelines can be less efficient, since the data is transformed multiple times as it is queried, rather than being transformed once before it is loaded.


Both ETL and ELT pipelines have their own strengths and weaknesses, and the best approach for a given situation will depend on the specific requirements of the data pipeline. ETL pipelines are generally more suitable for large, batch-oriented data pipelines, while ELT pipelines are more suitable for real-time, interactive data pipelines

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