PostgreSQL Connector

This solution demonstrates an integration between DecisionRules and a PostgreSQL database, utilizing it as a source for data retrieval. The difference between multi-row and single-row query nodes is mentioned.

The primary objective of this flow is to allow users to filter geographic groups and retrieve a list of countries that match those groups. The flow automates the process of querying a country database.

Solution Components

• Decision Flow PostgreSQL Connector: The core logic that processes user input, queries the database, and populates the flow’s output.
• RDBMS Node (selectCountries): Queries the  lov_country_region_table  using the user-provided string to find matching geographical groups and provides a list of countries within those groups. Each country is then processed through iteration over every item returned by the query.
• Append Node (arrayAppend): Within the iteration (loop) over every country, appends the country name to the end of the output parameter countriesList  (an array).
• Assign Node (assignOutput): Assigns the total number of retrieved countries to the output parameter numberOfCountries.

• Prerequisites: A PostgreSQL database must be accessible to the DecisionRules backend with the alias conn-postgresql-templates.

• Setup: Use the provided DDL and INSERT nodes to create the source table (templates.lov_country_region_table) and populate it with the sample data provided in the template.

• More details could be found in the main flow description - in the Flow Designer, select in the Sidebar the Rule Settings  and scroll down to Description