How-To: Neo4j ETL Tool

[adam_cowley]

This step is where the actual translation of the relational data into graph data happens. There are three rules the tool uses to convert from relational to graph.

• A table with a foreign key is treated as a join and imported as a node with a relationship

• A table with 2 foreign keys is treated as a join table and imported as a relationship

• A table with >2 foreign keys is treated as n intermediate node and imported as a node with multiple relationships

Those rules create a graph data model like the one below.

This example is using the popular Northwind data set. You can download and test this data set with the links further on this page.

This is where you can edit the mapping to change any of the translations, such as property names, data types, and relationships.

You can use the mouse to zoom in on the model or drag the image to focus on certain areas of the graph. If you do not see a component you are looking for, you can start typing the entity name in the search bar on the left side of the pane. Any matching results will show immediately.

Nodes and relationships are listed in respective tabs on the left side. To update, simply click the entity in the list. The tool also allows you to skip any nodes or relationships that you do not want to import to the graph. In the screenshot below, we have chosen to skip the UsState nodes because there are no relationships, so the data is less valuable to us in graph format. However, we could still choose to import those nodes and later refactor the graph to create relationships from those nodes to others in the graph.

To edit the details of mappings, click on the pencil icon next to entity in the list or double click on the entity in the visualization on the right. A popup box will list the fields and offer options for any changes. You can click Save to apply your changes to the graph.

Oftentimes, the relationship types will be defaulted to meaningless names for a graph, so we can update them with more meaningful names for improved data context. The image below shows an example of some changes to relationship types.

Once you have made any changes here, you can click Save Mapping. The status of the change will show in a blue (success) or red (error) message bar at the top of your window. If successful, you can click Next to go to the import step.

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This is a companion discussion topic for the original entry at https://neo4j.com/developer/neo4j-etl/