Query the Data Delivery Network

The 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 darprotow_enrollment_status_of_active_tow_truck table in this repository, by referencing it like:

"cityofnewyork-us/darprotow-enrollment-status-of-active-tow-truck-q5u8-89nv:latest"."darprotow_enrollment_status_of_active_tow_truck"

or in a full query, like:

SELECT
    ":id", -- Socrata column ID
    "license_status", -- Indicates the current status of the license.
    "city", -- The city where the business is located.
    "y_coordinate", -- Y Coordinate where the business is located
    "unit", -- The unit number of the business' address.
    "bbl", -- The Borough-Block-Lot number where the business is located.
    "longitude", -- The longitudinal coordinate where the business is located.
    "x_coordinate", -- X Coordinate where the business is located
    "darp_enrollment_status", -- Indicates if the tow truck company is currently enrolled in the DARP program
    "unit_type", -- The type of unit of the business' address.
    "state", -- The state where the business is located.
    "building_number", -- The building number where the business is located.
    "nta", -- The Neighborhood Tabulation Area where the business is located.
    "borough", -- The NYC Borough where the business is located.
    "dba_trade_name", -- The "Doing Business As" or "Trade Name" registered with the NYS Department of State.
    "census_tract", -- The 2010 Census Tract where the business is located.
    "rotow_enrollment_status", -- Indicates if the tow truck company is currently enrolled in the ROTOW program
    "street", -- The name of the street where the business is located.
    "business_name", -- The legal business name as filed with the New York State Secretary of State or County Clerk or, if an individual, the person’s first name and last name.
    "latitude", -- The latitudinal coordinate where the business is located.
    "bin", -- The Building Identification Number where the business is located.
    "police_precinct", -- Police Precinct where the business is located.
    "census_block_2010_", -- The 2010 Census Block where the business is located.
    "council_district", -- The NYC City Council District where the business is located.
    "community_district", -- The NYC Community District where the business is located.
    "dca_license_number", -- An identification number issued to a business or individual when their license application is approved by DCWP.
    "postcode", -- The ZIP Code where the business is located.
    "business_unique_id" -- An identification number assigned by DCWP to track unique businesses across its systems. 
FROM
    "cityofnewyork-us/darprotow-enrollment-status-of-active-tow-truck-q5u8-89nv:latest"."darprotow_enrollment_status_of_active_tow_truck"
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 cityofnewyork-us/darprotow-enrollment-status-of-active-tow-truck-q5u8-89nv with SQL in under 60 seconds.

This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.cityofnewyork.us. When you querycityofnewyork-us/darprotow-enrollment-status-of-active-tow-truck-q5u8-89nv: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)"

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.cityofnewyork.us, 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 \
  "cityofnewyork-us/darprotow-enrollment-status-of-active-tow-truck-q5u8-89nv" \
  --handler-options '{
    "domain": "data.cityofnewyork.us",
    "tables": {
        "darprotow_enrollment_status_of_active_tow_truck": "q5u8-89nv"
    }
}'

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, cityofnewyork-us/darprotow-enrollment-status-of-active-tow-truck-q5u8-89nv is just another Postgres schema.