Dimensions > Adding additional columns
  
Adding additional columns
With the columns of the dimension table displayed in the middle pane, this pane is considered a drop target for additional columns.
It is a simple matter therefore to select columns from other load tables and to drag these columns into the middle pane. The following column list is from the product table as supplied in the tutorial data set.
The source table shows where each column was dragged from. Although not the case in the tutorial, it is often common to have columns of the same name coming from different tables. In the example above the description column is acquired from the load_product, load_prod_group and load_prod_subgroup tables. In order that the dimension table be created we need to assign these columns unique names, so for this example the last two columns in question have been renamed to group_description and subgroup_description.
There are a number of columns that do not have a source table. These columns have been added by QAD Data Warehouse Designer, and are added depending on earlier choices. A description of these columns follows.
Column name
description
dim_product_key
The unique identifier (artificial key) for the dimension. This key is used in the joins to the fact table. It is generated via a sequence (Oracle) or identity (SQL Server) associated with the table, except for the date dimension where it has the form YYYYMMDD
dss_start_date
Used for slowly changing dimensions. This column provides a date time stamp when the dimension record came into existence. It is used to ascertain which dimension record should be used when multiple are available.
dss_end_date
Used for slowly changing dimensions. This column provides a date time stamp when the dimension record ceased to be the current record. It is used to ascertain which dimension record should be used when multiple are available.
dss_current_flag
Used for slowly changing dimensions. This flag identifies the current record where multiple versions exist.
dss_source_system_key
Added to support dimensions that cannot be fully conformed, and the inclusion of subsequent source systems. See the ancillary settings section for more details.
dss_version
Used for slowly changing dimensions. This column contains the version number of a dimension record. Numbered from 1 upwards with the highest number being the latest or current version. It forms part of the unique constraint for the business key of a slowly changing dimension.
dss_update_time
Indicates when the record was last updated in the data warehouse.
dss_create_time
Indicates when the record was first created in the data warehouse