Query Chain execution using Projection transformation

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Query Chain execution using Projection transformation

A Projection Transformation in Query Chain is used to change the existing Data Type in any column(s) and can also use to add the Alias Name column if required. Let’s execute QC using Projection transformation.

To learn more, let us walk through the below procedure:

• Click the ‘Query Studio’ module.
• Hover on the ‘Query Builder’ snippet.
• Click the ‘Query Chain’ option.

• The user is navigated to the new Query Chain session page.

• From the ‘Data Source’ tab, let’s drag and drop an ‘RDBMS Table’ icon onto Query Chain create and edit page.

Note: All other Data Source icons including ‘RDBMS Table’ gets disabled as the user drags it onto Query Chain session page.

• Double tap the ‘Read data from Table’ widget.

• A ‘Read data from table’ pop-up window is displayed.
• Let’s select ‘PostgreSQL’ from ‘Database Type’ drop-down list and ‘PostgreSQL Northwind-QA’ from ‘Connection Name’ drop-down list.
• Click the ‘Navigator’ button.

• A ‘Navigator’ slide screen is displayed on the right side of the page.
• Let’s select the ‘Order_details’ table from the ‘Public’ schema.

• Click the ‘Order_details’ table to pick the table.
• Click the ‘Select’ button.

• This action saves the ‘RDBMS table’ widget data by closing it.
• The user is navigated to the Query Chain session page.
• Click the ‘Transformations’ tab.

• Let’s drag and drop ‘Projection’ icon onto the Query Chain session page.
• Double tap the ‘Transform the data from <Data Source>’ widget.

• A ‘Transform the data from Data Source’ pop-up window is displayed.

Note: By default, all the Column Names are selected.

• Let’s change the ‘unitprice’ column Data Type to ‘Decimal’ from ‘float4.’
• Click the ‘Add Column’ button.

• This action displays a new screen.
• Let’s add ‘Total’ under ‘Column Name’ and ‘Data Type’ as ‘Decimal.’
• Let’s add the formula as Productid*unitprice=Total.
• Click the ‘Save’ button.

• This action displays the new column added (Total).
• Click the ‘Save’ button.

• This action closes the ‘Projection’ widget saving its data.
• The user is navigated to the ‘Query Chain’ session page.
• Click the ‘Output’ tab.

• Let’s drag and drop an ‘RD Output’ icon.
• Double tap the ‘RD Output’ widget.

• An ‘RD Output’ pop-up window is displayed.
• Click the ‘Select’ button.

• This action closes the ‘RD Output’ widget saving its data.
• Click the ‘Execute Now’ button.

• A green color tick mark indicates the Query Chain is executed successfully.
• A monitor mode is enabled.
• Let’s click on the ‘RD Output’ count icon (2155).

• This action navigates the user to the ‘Results’ tab displaying the executed data.
• The condition ‘producdid*unitprice’ should be equal to ‘Total.’