JOIN and WHERE

Typically, data lineage tools provide information about the immediate movement of data within the database:

CREATE VIEW v1
AS 
  SELECT c1
  FROM t1

Data from the column t1.c1 flows into v1.c1:

However, this data might be insufficient when it comes to refactoring. For instance, when certain columns aren't involved in the data movement but are only involved in JOIN or WHERE clauses:

CREATE VIEW v2
AS 
  SELECT c1
  FROM t1
    JOIN t2 ON t1.id = t2.parent_id
  WHERE 
    t1.c2 > t2.f2

Usually, data lineage tools won't provide information about columns t1.id, t1.c2, t2.parent_id, t2.f2, but at Dwh.dev, we've made them visible!