JDBC connector for Oracle/SQL connector

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07-29-2020 12:00 PM
JitendruduLacaraju1
New Contributor

I am writing a JDBC connector to consume JSON input and output it to a SQL Table to store the geoevents. Thoughts?

Branched from the discussion:  GeoEvent process Oracle/SQL connector

1 Reply
RJSunderman
Esri Regular Contributor

Hello Jitendrudu

When replies were written for the original thread Re: GeoEvent process Oracle/SQL connector I don't think the GeoEvent Manager supported publishing a feature service. The functional server role for licensing hadn’t been invented yet and GeoEvent Server was still being referred to as the GeoEvent Processor Extension for ArcGIS Server.

In recent releases, however, you can use GeoEvent Manager to publish Hosted Feature Layers to your Enterprise portal or map/feature services to a stand-alone ArcGIS Server. So on the one hand, nothing has changed with regard to the interface between GeoEvent Server and an RDMBS table. The interface is still a feature service since GeoEvent Server can only make REST requests against an Esri ArcGIS Server feature service to add or update feature records. But on the other, you can now publish feature services which do not necessarily have Geometry.

A feature service is typically published using a client, like ArcMap, which will not allow you to publish a feature service without a geometry. ArcMap defines a feature class as a collection of feature records and a feature record is a data structure with both geometry and attributes describing some object in the real-world. GeoEvent doesn’t make the same assumptions regarding Geometry that ArcMap does though. Real-time data streaming from a sensor whose position does not change wouldn’t necessarily include a geometry or coordinate values with its data. GeoEvent Server doesn’t assume that all data records will have geometry. To GeoEvent Server, “geometry” is just another type of attribute like a String or a Date.

Say, for example, you were to create a GeoEvent Definition with two attribute fields – one a Date the other a String – and didn’t include a Geometry field type. You can use any release of GeoEvent after 10.6.1 to publish a feature service to the ArcGIS Server beneath which GeoEvent Server is running. Without a Geometry, to any other client, the feature class's table looks like a non-spatial table. But ArcGIS Server provides a feature service interface to the table allowing you to write the Date and String data you want to it without having a Geometry.

You would still configure an Update a Feature output, and made sure to use a Field Mapper to map whatever schema your inbound connector uses to adapt data you receive to the feature service’s schema (PostGRE, for example, insists on using only lower-case field names; Oracle only upper-case field names). You shouldn't have any problem ingesting some sample data that has no geometry and using GeoEvent Server to add/update “feature records” via the feature service. The data records in the RDBMS simply have no geometry … so you won’t be able to add them to a web map as a feature layer for example, but I can query the data at REST. I assume if I had some other database client able to query from the data table I’d be able to retrieve the data that way, rather than going through the feature service’s REST interface to query the data.

This would be a lot easier that developing a custom outbound transport which understood how to connect to the RDBMS using ODBC. This is possible, but I don’t know how feasible it is, really, given the inter-dependency of bundles in the Java system framework that underlies GeoEvent Server. GeoEvent Server’s whole design, in this case, assumes that you’ll be able to work through a feature service to access feature records.

Hope this information is helpful –
RJ

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