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 employee_counts_by_industry_in_colorado table in this repository, by referencing it like:

"colorado-gov/employee-counts-by-industry-in-colorado-cjkq-q9ih:latest"."employee_counts_by_industry_in_colorado"

or in a full query, like:

SELECT
    ":id", -- Socrata column ID
    "taxwage", -- Total taxable wages.
    "avgwkwage", -- Average weekly wage per worker.
    "totwage", -- The total wages paid to all workers in the industry for the period.
    "topempav", -- Average employment for the quarter or year of the top employer for the specified geography and industry code
    "mnth3emp", -- Employment on the third month of the quarter.
    "mnth1emp", -- Employment on the first month of the quarter.
    "avgemp", -- The number of workers employed in the industry.
    "estab", -- The number of employer establishments in the industry. (reporting units)
    "prelim", -- Preliminary/revised flag 0 = Not Preliminary, 1 = Preliminary
    "codetitle", -- The descriptive title for this industry code.
    "indcode", -- A code used in the classification of establishments by type of activity in which they are engaged. For codes not 6 characters long, left justify and blank (ASCII 32) fill. Either SIC or NAICS code can be used. A siccode of 9999 means non-classifiable; industry not specified.
    "period", -- Period Code. Will be set to '00' where periodtype is annual.
    "periodyear", -- Character representation of calendar-year (e.g. 2000).
    "area", -- Six-digit code assigned to represent a geographic area. Front fill with zeroes.
    "areatyname", -- Descriptive title of the areatype.
    "areatype", -- Code describing type of geographic area: e.g. county, service delivery area, MSA.
    "areaname", -- Geographic area name.
    "stfips", -- State FIPS code.
    "statename", -- State name.
    "mnth2emp", -- Employment on the second month of the quarter.
    "ownertitle", -- Title of ownership.
    "stateabbrv", -- The two letter state abbreviation.
    "ownership", -- Ownership is a two-digit indicator that identifies the employer by public or private ownership.
    "firms", -- The number of firms in the industry.
    "indcodty", -- Code describing the industry code type.
    "suppress", -- An indicator that the record contains confidential data that must be suppressed for public use. 0 = Not Suppressed, 1 = Suppress employment & wage data
    "pertypdesc", -- A description of the period type.
    "periodtype", -- Code describing type of period (e.g. Annual, quarterly, monthly, etc.).
    "contrib" -- Employer contributions to the UI fund.
FROM
    "colorado-gov/employee-counts-by-industry-in-colorado-cjkq-q9ih:latest"."employee_counts_by_industry_in_colorado"
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 colorado-gov/employee-counts-by-industry-in-colorado-cjkq-q9ih with SQL in under 60 seconds.

This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.colorado.gov. When you querycolorado-gov/employee-counts-by-industry-in-colorado-cjkq-q9ih: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.colorado.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 \
  "colorado-gov/employee-counts-by-industry-in-colorado-cjkq-q9ih" \
  --handler-options '{
    "domain": "data.colorado.gov",
    "tables": {
        "employee_counts_by_industry_in_colorado": "cjkq-q9ih"
    }
}'

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, colorado-gov/employee-counts-by-industry-in-colorado-cjkq-q9ih is just another Postgres schema.