Data modelling in Power BI: Joins, Relationships, and Schemas Explained.

data modelling It is the process of analyzing and defining different data types and the relationships between them SQL joins we shall assume Table A(left) and Table B(right) as data sets given to us Inner Join: This returns only rows with matches from both table A and B. Left Join: Returns all rows from the left table(A) and matching rows from the right table(B). Nulls from table B will be returned if no matches. Right Join: Returns all rows from the right table(B) and matching rows from the left table(A). No matches will appear as nulls. Full Outer Join: Returns all rows from both tables. Left Anti: Returns rows from the left table (A) that have no match on the right table (B). Right Anti: Returns all rows from the right table(A) that have no matches on the left table(B). Illustrations of Joins Power BI relationships Relationships connect tables using keys 1. One-to-Many(1:M): Commonest that links one table to many Example: One patient that has many visits. 2. Many-to-Many(M:M): Links