RELATIONSHIP SCHEMA AND JOINS

Power BI is built in relationships. A well designed relationship schema enables accurate calculations and efficient analysis.

1. What is a relationship schema A relationship schema describes how tables in your model are connected. With these relationships Power BI can combine data from multiple tables. Tables are related using columns.

Types of relationship schema

1. One to one one record correspondence between the first and the second table.
2. One to many One record in the first table can link to multiple records in the second table.

3. Many to many
   Records in one table are related to multiple records in another table.

4. JOINS
   Joins are used to combine data from two tables before its loaded in the model.

Types of joins
1.Inner join- Returns matching rows from both tables
2.Full join/full outer join- all rows from both tables matched or unmatched.
3.Left join/Left outer join- all rows from the left table match with the right table.
4.Right join/ right outer join- all rows from the right table match with the left table.
5.Left anti join-All rows from the left table with no match to the right table.
6.Right anti join- All rows from the right table with no match to the right table.