Relationships connection

[Moh_Ashraf]

I have a problem in relationships connections between two tables:

Table 1 (Main): For recording orders, so it has many colums and categories.

Table 2 (Working Hours): it has a Month, year and section code.

When I make a relation many to many it gives an error as shown in the attachement.

[Deku]

It is not a error, it is a warning. Many:many relationships are weak relationships, which can have performance implications when the relationship has a high cardinality 

Looking at your model it looks like you want to join the two tables with multiple fields that you want want to apply at the same time. Only a single join between two tables can be a active at a time. You should consider creating a single column on both sides of the join that would be used in the relationship. This could simply be the concatenatination of all the fields you want to contribute to the join. In your case this would be year, month and location

[Moh_Ashraf]

When i complete creation of the 3 relationship many to many, I face a problem in slicer funcionality between two tables.

So, when make slicer from (Working hours) Table, it doesn't reflect on (main) table.

[Deku · Accepted solution]

That is because only 1 of your 3 relationships is active, and only one can be active. You need to create a single column that can deal with the join.