Lineage of Views¶
The “Lineage” tab displays a graph of the data sources and views used to build the current view (considering it is not a base view). It also displays the source where the information of each field comes from. As explained in the graph for associations, this graph allows you to zoom in/out and to move through it with the mouse or with the arrows in the image. You can also export the current image.
By clicking on a node, you can see all its data: name, type, projected fields, where conditions, join conditions, etc., as shown in Data lineage for Customer view.
You can also inspect the data lineage for a specific field. On the left side of the dialog, there is a list of all the view’s fields. By clicking on one of the fields, all the views and data sources that participate in the creation of this field will be highlighted (in green). For instance, if a field f is obtained by evaluating an expression involving two fields f1 and f2 from different data sources, Virtual DataPort will highlight the data sources (and their associated views) providing f1 and f2, and the view where the expression to obtain the value of f is defined. As an example, if you select the field name, only the left side of the tree is highlighted (green color). On mouse over (see Data lineage for a field: mouse over), you can see the name of the field of the view involved in the lineage and if you click on the node (see Data lineage for a field: information about a node), the same information as shown in Data lineage for Customer view appears, but with the field involved in the lineage highlighted (bold font).
It is important to note that the information shown within the data lineage depends on the permissions of the current user. This way:
- To see the data sources, the user must have (at least)
METADATAprivileges over them; otherwise, they will not appear in the graph.
- To see the views, the user must have (at least)
METADATAprivileges over them; otherwise, a node with the legend “No Privileges” will appear.