Query the Data Delivery Network
Query the DDNThe easiest way to query any data on Splitgraph is via the "Data Delivery Network" (DDN). The DDN is a single endpoint that speaks the PostgreSQL wire protocol. Any Splitgraph user can connect to it at data.splitgraph.com:5432 and query any version of over 40,000 datasets that are hosted or proxied by Splitgraph.
For example, you can query the air_quality_continuous_emission_monitoring_system table in this repository, by referencing it like:
"pa-gov/air-quality-continuous-emission-monitoring-system-5s9f-3bq4:latest"."air_quality_continuous_emission_monitoring_system"or in a full query, like:
SELECT
":id", -- Socrata column ID
"municipality_name", -- The Municipality name where the Continuous Emission Monitoring Data Processing System (CEMDPS) Facility is located.
"county_name", -- The Pennsylvania County name where the Continuous Emission Monitoring Data Processing System (CEMDPS) Facility is located.
"longitude_minutes", -- Longitude Minutes only of the Continuous Emission Monitoring Data Processing System (CEMDPS) Facility.
"latitude_seconds", -- Latitude Seconds only of the Continuous Emission Monitoring Data Processing System (CEMDPS) Facility.
"zip_code", -- Zip Code of the Continuous Emission Monitoring Data Processing System (CEMDPS) Facility.
"city", -- City of the Continuous Emission Monitoring Data Processing System (CEMDPS) Facility.
"address", -- Address of the Continuous Emission Monitoring Data Processing System (CEMDPS) Facility.
"determination_method", -- The method used to derive the emission amount for the report date and report hour.
"monitoring_status", -- The operating status of the monitoring device on the report date and report hour.
"monitoring_code", -- Code that defines the operating status of the monitoring device on the report date and report hour.
"process_code", -- Code that defines the operating status of the air emissions source on the report date and report hour.
"amount", -- Emission amount in units defined by emission result.
"hour", -- Hour of the report date the emission was collected by the monitoring device.
"report_date", -- Calendar date the emission was collected by the monitoring device.
"pollutant", -- Type of emitted pollutant.
"geocoded_column", -- A generic georeferenced Latitude & Longitude point within the county. These points can be used to create visualizations such as maps to show the data by county.
"longitude_seconds", -- Longitude Seconds only of the Continuous Emission Monitoring Data Processing System (CEMDPS) Facility.
"year_quarter", -- Year and quarter of reported data
"uom", -- Unit of Measure
"source_name", -- Name of source at the facility.
"state", -- State of the Continuous Emission Monitoring Data Processing System (CEMDPS) Facility.
"latitude_degrees", -- Latitude Degrees only of the Continuous Emission Monitoring Data Processing System (CEMDPS) Facility.
"report_type", -- Determines if submitted body of data for the year/quarter should be processed as regular, sample, or indicator.
"determination_method_code", -- A number that determines the specific code that defines the method used to derive the emission amount for the report date and report hour.
"process_status", -- The operating status of the air emissions source on the report date and report hour.
"longitude_degrees", -- Longitude Degrees only of the Continuous Emission Monitoring Data Processing System (CEMDPS) Facility.
"latitude_minutes", -- Latitude Minutes only of the Continuous Emission Monitoring Data Processing System (CEMDPS) Facility.
"address_supplement", -- Supplemental address of the Continuous Emission Monitoring Data Processing System (CEMDPS) Facility.
"facility_name", -- Name of the Continuous Emission Monitoring Data Processing System (CEMDPS) Facility.
":@computed_region_rayf_jjgk",
":@computed_region_r6rf_p9et",
":@computed_region_amqz_jbr4",
":@computed_region_d3gw_znnf",
":@computed_region_nmsq_hqvv"
FROM
"pa-gov/air-quality-continuous-emission-monitoring-system-5s9f-3bq4:latest"."air_quality_continuous_emission_monitoring_system"
LIMIT 100;Connecting to the DDN is easy. All you need is an existing SQL client that can connect to Postgres. As long as you have a SQL client ready, you'll be able to query pa-gov/air-quality-continuous-emission-monitoring-system-5s9f-3bq4 with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.pa.gov. When you querypa-gov/air-quality-continuous-emission-monitoring-system-5s9f-3bq4:latest on the DDN, we "mount" the repository using the socrata mount handler. The mount handler proxies your SQL query to the upstream data source, translating it from SQL to the relevant language (in this case SoQL).
We also cache query responses on the DDN, but we run the DDN on multiple nodes so a CACHE_HIT is only guaranteed for subsequent queries that land on the same node.
Query Your Local Engine
bash -c "$(curl -sL https://github.com/splitgraph/splitgraph/releases/latest/download/install.sh)"Read the installation docs.
Splitgraph Cloud is built around Splitgraph Core (GitHub), which includes a local Splitgraph Engine packaged as a Docker image. Splitgraph Cloud is basically a scaled-up version of that local Engine. When you query the Data Delivery Network or the REST API, we mount the relevant datasets in an Engine on our servers and execute your query on it.
It's possible to run this engine locally. You'll need a Mac, Windows or Linux system to install sgr, and a Docker installation to run the engine. You don't need to know how to actually use Docker; sgrcan manage the image, container and volume for you.
There are a few ways to ingest data into the local engine.
For external repositories (like this repository), the Splitgraph Engine can "mount" upstream data sources by using sgr mount. This feature is built around Postgres Foreign Data Wrappers (FDW). You can write custom "mount handlers" for any upstream data source. For an example, we blogged about making a custom mount handler for HackerNews stories.
For hosted datasets, where the author has pushed Splitgraph Images to the repository, you can "clone" and/or "checkout" the data using sgr cloneand sgr checkout.
Mounting Data
This repository is an external repository. It's not hosted by Splitgraph. It is hosted by data.pa.gov, and Splitgraph indexes it. This means it is not an actual Splitgraph image, so you cannot use sgr clone to get the data. Instead, you can use the socrata adapter with the sgr mount command. Then, if you want, you can import the data and turn it into a Splitgraph image that others can clone.
First, install Splitgraph if you haven't already.
Mount the table with sgr mount
sgr mount socrata \
"pa-gov/air-quality-continuous-emission-monitoring-system-5s9f-3bq4" \
--handler-options '{
"domain": "data.pa.gov",
"tables": {
"air_quality_continuous_emission_monitoring_system": "5s9f-3bq4"
}
}'That's it! Now you can query the data in the mounted table like any other Postgres table.
Query the data with your existing tools
Once you've loaded the data into your local Splitgraph engine, you can query it with any of your existing tools. As far as they're concerned, pa-gov/air-quality-continuous-emission-monitoring-system-5s9f-3bq4 is just another Postgres schema.