Defining a Fact Relationship | Microsoft Docs
If you add a dimension to a measure group/cube/fact table the and define the relation between your dimension key and the fact table. SSAS dimensions are groups of attributes based on columns from tables the key attribute, we cannot join the dimension and fact table, and therefore, If there is no relation between a Dimension and Measure Group, there. Measures and KPIs are very important aspects of an OLAP/SSAS solution Explain different types of relationships between Facts and Dimensions. Fact: In a Fact relationship, the dimension table and the fact table are one.
On the Welcome to the Dimension Wizard page, click Next. On the Select Creation Method page, verify that the Use an existing table option is selected, and then click Next. In the Main table list, select InternetSales.
Dimension Relationships | Microsoft Docs
On the Select Related Tables page, clear the check boxes beside all of the tables, and then click Next. On the Select Dimension Attributes page, click the check box in the header twice to clear all of the check boxes. The Sales Order Number attribute will remain selected because it is the key attribute. On the File menu, click Save All. In the NameColumn property cell, click the browse button Although changing the storage mode to ROLAP will save processing time and storage space, it occurs at the expense of query performance.
To add the newly created dimension to the Analysis Services Tutorial cube as a cube dimension, switch to Cube Designer.
In the Add Cube Dimension.
Notice that the Internet Sales Order Details cube dimension is automatically configured as having a fact relationship, as shown by the unique icon. Click the browse button The Define Relationship dialog box opens. Notice that you cannot configure any of the properties.
- Dimension Relationships
- Lesson 5: Defining Relationships Between Dimensions and Measure Groups
- Fact dimension relationships
The following image shows the fact relationship properties in the Define Relationship dialog box. After deployment has successfully completed, click the Browser tab in Cube Designer for the Analysis Services Tutorial cube, and then click the Reconnect button. Clear all measures and hierarchies from the data pane, and then add the Internet Sales-Sales Amount measure to the data area of the data pane.
Fact dimension relationships « Chris Webb's BI Blog
Filtering to limit the sales orders returned to a single customer lets the user drill down to the underlying detail in a large fact table without suffering a significant loss in query performance. A relationship between a dimension and a measure group consists of the dimension and fact tables participating in the relationship and a granularity attribute that specifies the granularity of the dimension in the particular measure group.
Regular Dimension Relationships A regular dimension relationship between a cube dimension and a measure group exists when the key column for the dimension is joined directly to the fact table. This direct relationship is based on a primary key-foreign key relationship in the underlying relational database, but might also be based on a logical relationship that is defined in the data source view.
A regular dimension relationship represents the relationship between dimension tables and a fact table in a traditional star schema design.
For more information about regular relationships, see Define a Regular Relationship and Regular Relationship Properties. Reference Dimension Relationships A reference dimension relationship between a cube dimension and a measure group exists when the key column for the dimension is joined indirectly to the fact table through a key in another dimension table, as shown in the following illustration.
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A reference dimension relationship represents the relationship between dimension tables and a fact table in a snowflake schema design. When dimension tables are connected in a snowflake schema, you can define a single dimension using columns from multiple tables, or you can define separate dimensions based on the separate dimension tables and then define a link between them using the reference dimension relationship setting.
The following figure shows one fact table named InternetSales, and two dimension tables called Customer and Geography, in a snowflake schema. You can create a dimension with the Customer table as the dimension main table and the Geography table included as a related table.
A regular relationship is then defined between the dimension and the InternetSales measure group. Alternatively, you can create two dimensions related to the InternetSales measure group: You can then relate the Geography dimension to the InternetSales measure group using a reference dimension relationship using the Customer dimension.
In this case, when the facts in the InternetSales measure group are dimensioned by the Geography dimension, the facts are dimensioned by customer and by geography. If the cube contained a second measure group named Reseller Sales, you would be unable to dimension the facts in the Reseller Sales measure group by Geography because no relationship would exist between Reseller Sales and Geography. There is no limit to the number of reference dimensions that can be chained together, as shown in the following illustration.
SSAS Interview Questions on Measures, Actions, and Storage
For more information about referenced relationships, see Define a Referenced Relationship and Referenced Relationship Properties. Fact Dimension Relationships Fact dimensions, frequently referred to as degenerate dimensions, are standard dimensions that are constructed from attribute columns in fact tables instead of from attribute columns in dimension tables.
Useful dimensional data is sometimes stored in a fact table to reduce duplication. The table contains attribute information not only for each line of an order issued by a reseller, but about the order itself.