# Lineage and Impact Analysis

The *Lineage* diagram in Astera helps in tracing the data roots while the *Impact* diagram helps in identifying where that data is consumed in the data processes.

## **Overview**

Conducting data impact and lineage analysis is helpful in following business scenarios:

* To get a complete picture of your business data – where it is originating from, how it is transformed during the processing cycle, what target systems are impacted as a result
* To see how changing a data source will alter the established data processes
* How a specific data entity is related to other objects in a data model or an ETL flow
* To identify who has access to data and how the data is transformed at each step

The main purpose of conducting the impact and lineage analysis is to get a bird’s eye view of the journey of your business data, and how (at each level) a specific data entity will impact other entities and objects in your ETL project. When you have this information, you can:

* Make informed business decisions
* Do an impact analysis before adding a new data source or altering an existing one
* Protect and govern your enterprise data

Astera offers to create lineage and impact analysis diagrams at three levels:

1. Document level lineage
2. Object level lineage
3. Field level lineage

In this document, we will see how data lineage and impact feature works in Astera.

## **Sample Use-Case**

Here, we have a project comprising of two subflows, a dataflow, and a workflow document. These flows are interlinked.

![](/files/4UGJmVGNc30OR9LsI5jl)

Subflows are called in the dataflow through [*Subflow Transformation*](https://documentation.astera.com/v/astera-data-stack-v7/dataflows/transformations/subflow-transformation) object. *Subflow\_Union* performs [*Union Transformation*](https://documentation.astera.com/v/astera-data-stack-v7/dataflows/transformations/union-transformation) on incoming data, followed by *Subflow\_Aggregate* that uses [*Aggregate Transformation*](https://documentation.astera.com/v/astera-data-stack-v7/dataflows/transformations/aggregate-transformation) to calculate totals of price, quantity and discount based on *OrderID*. A *Data Quality Rule* is then applied to treat records with no discount values as errors and the validated data is written to a delimited file.

![](/files/dxmZNMOiuAkvMENxgyqw)

Workflow orchestrates this dataflow using a *Run Dataflow Task* object. Based on the criterion defined in the decision object, a notification email is sent to the administrator.

![](/files/aWxWoPnOjxJQ1tM0hUvc)

Let’s create Lineage and Impact diagrams for these flows at three levels.

## **Field Level Lineage**

Astera enables users to see data lineage and impact at the field level.

For instance, if you have a formula field in a dataflow, and you’d like to see the lineage (where the data is coming from in that field) and impact (what other fields/objects that field is impacting), you make use of the *Field Lineage* option available.

In this example, we want to see the field lineage for the *TotalUnitPrice* field in the *Data Quality Rules* object.

To see/create a field lineage diagram, right-click on the field and select *Show Lineage* from the context menu. The *Lineage and Impact* window will open up at the bottom of the screen.

![](/files/GwbNqHCnQpsGtCEED4bu)

This window provides a detailed map of the fields in the lineage and the fields in the impact of the *TotalUnitPrice* field.

![](/files/351q6ArnSSYwOv3D95TY)

If you are unable to see the *Lineage and Impact* window, go to *View > Lineage and Impact* or press Ctrl + Alt + O**.**

![](/files/5GoSxHQlLzYpqEc2TLzb)

Moreover, a new tab will open in Astera, showing you the *Lineage and Impact* diagram for the *TotalUnitPrice* field.

![](/files/kBoc0yjqsCU9sXQ6HIB2)

In the above screenshot, observe that the representative element for the *TotalUnitPrice* field is visibly prominent.

The blue links indicate the flow of data inside the *TotalUnitPrice* field from the fields in the *Lineage* to the fields in the *Impact*.

Links in black represent the flow of data of other fields inside the *Data Quality Rules* object.

## **Object Level Lineage**

When using several different objects in multiple flows within a single project, manually tracing the data roots of a particular object becomes difficult.

Astera makes tracing the data roots of an object simpler by providing the option to create object-level lineage and impact diagrams.

In this example, we want to create a Lineage and Impact diagram for the *DataQualityRules\_Task* (*Run Dataflow Task*) object used inside the workflow.

To create an object lineage diagram, right-click on the object’s header and select *Show Lineage* from the context menu.

![](/files/W4vzL3VYjXQv8wI7Qi4g)

A detailed map showing objects in the lineage and the objects in the impact of the *DataQualityRule\_Task* object can be seen in the *Lineage and Impact* window.

![](/files/3h82OHXuiaJR45mYPkII)

A new tab will open in Centerprise, showing you the *Lineage and Impact* diagram for the *DataQualityRules\_Task* object.

![](/files/7YI1zV23Vashtgg7n4GP)

In the above screenshot, see that the representative element for *DataQualityRule\_Task* is visibly prominent to indicate the object under focus.

The source object for the *DataQualityRule\_Task* object is called its *Lineage* and the target objects are called its *Impact*.

![](/files/XC0IobFc6LdqjHWBck8z)

## **Document Level Lineage**

Once field-level lineage and object-level lineage diagrams are created, users can view document-level lineage.

An Astera project can comprise multiple interlinked flow documents (subflows, dataflows, and workflows). Tracing which flows are linked to a particular flow document in question, becomes easier with a document-level lineage graph.

To see a document-level lineage, go to the Astera tab showing object lineage, right-click on any representative element in the lineage diagram, and select *Show Lineage for this Document* from the context menu.

In this example, we are creating a document-level lineage for the dataflow. On the same tab, Astera will create the document-level lineage and impact analysis diagram for the dataflow document.

![](/files/s6QKfdmy3ql4eaBB3JhY)

Observe that the lineage includes two subflows and the impact comprises of a workflow shown by their representative elements. These are the flows that the *DataQuality.Df* dataflow document is interlinked, which means that the data in this dataflow is coming from two subflow documents and further this dataflow is being called to a workflow.

![](/files/VaiquXmfLCcEJn9fPavj)

*The Lineage and Impact* window shows a map of documents in the lineage of *DataQuality.Df* and the document in its impact under separate headings.

![](/files/z1G2jwsktfGdTffD6nDl)

## **Alternative Method to see Data Lineage**

There are two ways a user can access data lineage and impact in Astera. One way is already defined in previous sections of this article.

The other way is directly from the *Project Explorer* panel.

To view document-level lineage, go to the *Project Explorer* panel, and right-click on *DataQuality.Df* node and select *Show Lineage* from the context menu.

![](/files/EKhLYHrZxvbtnKFP1iNl)

To view object-level lineage, expand the *Workflow\.Wf* node, right-click on the *DataQualityRule\_Task* object and select *Show Lineage* from the context menu.

![](/files/mzGyGYR38L4AkID6HgmA)

To view field-level lineage, expand the *DataQuality.Df* node then expands the *DataQualityRules* object, right-click on the *TotalUnitPrice* field, and select *Show Lineage* from the context menu.

![](/files/eE7s2PFZD3QAc2zgIHMm)

To check how many lineage graphs have been created by Astera, you can view its output.

To check the lineage output, go to *View > Output* or press Ctrl + Alt + O.

![](/files/TUH82YcW7Gc4911zaPzW)

An *Output* window opens, displaying the lineage graph output of the project. This window will only show the output once the *Show Lineage* command has been executed.

![](/files/6jcjzjmTGAJv6VB4apCA)


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