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 governors_executive_budget_program_measures_sfy table in this repository, by referencing it like:

"pa-gov/governors-executive-budget-program-measures-sfy-knxi-vhah:latest"."governors_executive_budget_program_measures_sfy"

or in a full query, like:

SELECT
    ":id", -- Socrata column ID
    "budget_book_budget_year", -- This is the State Fiscal Year when the program measure numbers in this row were submitted for the Governor's Executive Budget Book.
    "grants_provided_to_non_profit", -- Cultural and Historical Support Grants awarded to qualifying museums and historical organizations.for general operating support  This program excludes art museums which are funded by the Pennsylvania Council for the Arts. 
    "records_or_information", -- Individuals, institutions and governments incorporating the statewide historic preservation plan into their preservation and community development plans. 
    "number_of_historic_resources", -- Documented historical and cultural places as well as recorded archaeological sites placed in the PA-SHARE database for online accessibility. 
    "images_added_to_pa_power", -- Images representing digitized records in the Pennsylvania State Archives placed online to make the holdings more accessible.
    "records_added_online_to", -- Records documenting specific items/artifacts in PHMC's museum collections placed online to make them more accessible
    "fiscal_year", -- Fiscal year for which the program measure values in this row are applicable. Fiscal Years 2020-21 and 2021-22 are estimated amounts based on agency projections.
    "promote_the_use_of_statewide", -- Older paper records stored in the State Records Center on behalf of state agencies as per their retention schedule requested for retrieval by those agencies. 
    "environmental_reviews", -- Represents the number of projects submitted by federal and state agencies reviewed by the Pennsylvania State Historic Preservation Office (PA SHPO) reviews to determine if they will impact significant cultural and historical resources and, if so, how to address and resolve those effects, as required by the National Historic Preservation Act of 1966.
    "trained_practitioners_and", -- Individuals who have received PHMC-sponsored training on preservation practices, record maintenance and community preservation. 
    "planning_and_construction", -- Dollars awarded/spent for preservation planning and construction projects. 
    "onsite_paid_visitation_at_phmc" -- Visitors paying to visit PHMC sites and museums - discounted admission included.  PHMC welcome many visitors free of charge for special programs, free days and recreational use but the paid visitation  number is tracked through our ticketing system and is more consistent than unpaid or recreational visitors which are sometimes estimated and open to greater chance of error. 
FROM
    "pa-gov/governors-executive-budget-program-measures-sfy-knxi-vhah:latest"."governors_executive_budget_program_measures_sfy"
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/governors-executive-budget-program-measures-sfy-knxi-vhah 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/governors-executive-budget-program-measures-sfy-knxi-vhah: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.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/governors-executive-budget-program-measures-sfy-knxi-vhah" \
  --handler-options '{
    "domain": "data.pa.gov",
    "tables": {
        "governors_executive_budget_program_measures_sfy": "knxi-vhah"
    }
}'

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/governors-executive-budget-program-measures-sfy-knxi-vhah is just another Postgres schema.