Describe differences of each `incremental_strategy` option

[dbeatty10]

Contributions

• [X] I have read the contribution docs, and understand what's expected of me.

Link to the page on docs.getdbt.com requiring updates

https://docs.getdbt.com/docs/build/incremental-models

What part(s) of the page would you like to see updated?

It is not clear here how each option for incremental_strategy differs from the others:

• append
• merge
• insert_overwrite
• delete+insert

Explanations that can be used for inspiration:

• https://medium.com/indiciumtech/understanding-dbt-incremental-strategies-part-1-2-22bd97c7eeb5
  • https://medium.com/p/add59889ea17
• https://hevodata.com/learn/dbt-incremental-strategy/#3
• https://towardsdatascience.com/two-completely-different-types-of-dbt-incremental-models-in-bigquery-db794cbe022c

Summary of things to improve

• explain differences between each strategy
• explain pros/cons of each strategy
• explain how each strategy does/doesn't map onto Type 1/2 Slowly Changing Dimensions (SCD)

Additional information

This issue originally described four separate issues that were each related to incremental strategies. Since then, we've split them each into their own issues:

• https://github.com/dbt-labs/docs.getdbt.com/issues/4633
• https://github.com/dbt-labs/docs.getdbt.com/issues/4634
• https://github.com/dbt-labs/docs.getdbt.com/issues/4635

[jtcohen6]

Very relevant & very overdue:

• https://github.com/dbt-labs/docs.getdbt.com/issues/1761