Query Chain execution using Projection transformation

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Query Chain using Projection Transformation

Select, rename, and derive columns from a data stream using the Projection widget.

Overview

The Projection transformation selects, renames, or derives columns from the input data stream. It is used to shape the data — keeping only required columns, adding computed fields, or renaming columns — before passing the result to the next stage in the chain.

Note: Ensure all required connection profiles are configured in the Administration module before building queries or Query Chains in this workflow.

Prerequisites

• You are logged in to Data Trust with a Pro-User or Admin Pro-User role.
• A Query Chain with a data source widget has been configured.

Steps

Path: Data Trust › Query Studio › Query Chain using Projection Transformation

Figure 1: Query Studio_Query Builder_Query Chain

Navigate to the Query Studio module and select Query Studio_Query Builder_Query Chain to open the Query Builder workspace. This is the starting point for creating, editing, and managing queries in Data Trust.

Figure 2: Query Chain create page

The Query Chain create page is the main workspace for building and editing queries. Use the canvas to write SQL, add data sources, connect transformations, and configure output options.

Figure 3: Read data from table widget

This step shows Read data from table widget in the Query Chain using Projection Transformation workflow. Follow the on-screen prompts to complete this configuration step before proceeding to the next stage.

Figure 4: Read data from table_popup window

This step shows Read data from table_popup window in the Query Chain using Projection Transformation workflow. Follow the on-screen prompts to complete this configuration step before proceeding to the next stage.

Figure 5: Snowflake_jdbc_Database Type_Connection Name_Navigator

Select the appropriate connection profile from the dropdown to link the query to its data source. Choosing the correct profile ensures the query reads from the intended database or system.

Figure 6: Navigator slide screen_SNOWFLAKE_SAMPLE_DATA

The Navigator panel displays the available databases, schemas, and tables for the selected connection. Expand the tree to locate the required table, then click Select to add it to the query.

Figure 7: Filter and Aggregation transformation from the RDBMS table widget

The Filter transformation restricts the records passing through the Query Chain to only those matching the specified conditions. Define the filter expression using field dropdowns, operator selectors, and value inputs, then save the widget.

Figure 8: Transformations tab

The Transformations tab lists all available data transformation widgets — Filter, Projection, Aggregation, Join, Pivot, Unpivot, and more. Drag the required transformation onto the canvas and connect it between the data source and output widgets.

Figure 9: Projection icon_Transform the data from data source widget

The Projection widget selects, renames, or derives columns from the input data stream. Use it to add computed columns, remove unnecessary fields, or rename columns before passing data to the next stage.

Figure 10: Transform the data from data source window popup

This step shows Transform the data from data source window popup in the Query Chain using Projection Transformation workflow. Follow the on-screen prompts to complete this configuration step before proceeding to the next stage.

Figure 11: Click the Save button

Click Save to persist the query or configuration to the Query Explorer. A confirmation message appears once the save completes, and the query is available for reuse in Query Chains and scenarios.

Figure 12: Click the Output tab

The RD Output widget captures the final result set from the Query Chain for use in downstream processes. Configure the output name and format, then save the widget to make the results accessible to other scenarios and reports.

Figure 13: Drag and Drop_RD Output widget

Drag the _Rd Output Widget widget from the palette and drop it onto the Query Chain canvas. Once placed, click the widget to open its configuration popup and complete the required settings.

Figure 14: RD Output popup window_Select button

The RD Output widget captures the final result set from the Query Chain for use in downstream processes. Configure the output name and format, then save the widget to make the results accessible to other scenarios and reports.

Figure 15: Click the Execute Now icon

Click Execute Now to run the query immediately and fetch the result set. The results appear in the Results tab, and the execution status is displayed in the progress indicator.

Figure 16: Click the RD Output count icon

The RD Output widget captures the final result set from the Query Chain for use in downstream processes. Configure the output name and format, then save the widget to make the results accessible to other scenarios and reports.

Figure 17: Results tab displaying the executed data

Click Execute Now to run the query immediately and fetch the result set. The results appear in the Results tab, and the execution status is displayed in the progress indicator.