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 bho_medication_fill_data_20102014 table in this repository, by referencing it like:

"ny-gov/bho-medication-fill-data-20102014-cc9j-4ujx:latest"."bho_medication_fill_data_20102014"

or in a full query, like:

SELECT
    ":id", -- Socrata column ID
    "age_group", -- Standardized Age Groups are either “Adult” or “Youth”.
    "metric_id", -- Numeric Code that uniquely identifies the Metric
    "quarter", -- Calendar quarter for which the metric is calculated: Q1, Q2, Q3, Q4 or some combination of one or more quarters
    "year_to_date_denominator", -- Value of the bottom of the "Rate" calculation for the Age Group, OMH Region, Performance Metric and Year to Date being examined.
    "denominator", -- Value of "bottom" of the calculation for the Age Group, OMH Region, Performance Metric and Quarter that is being examined. For Detailed Descriptions of the Denominator for each metric, see the “Detailed Metric Definitions” table in the data dictionary attached to this dataset.
    "description_of_metric", -- For more detail, see the “Detailed Metric Definitions” table in the data dictionary attached to this dataset.
    "row_created_date_time", -- Date and Time when data was generated (e.g. “12/19/2014 09:45:21”)
    "year", -- 4 Digit year for which the metric is calculated
    "indicator_domain_group", -- This is the domain group that the BHO Performance Indicator belongs to. For this dataset, the Domain Group is Medication Fill.
    "omh_region", -- Name of the OMH Region for which the Indicator is calculated
    "year_to_date_numerator", -- Value of the top of the "Rate" calculation for the Age Group, OMH Region, Performance Metric and Year to Date being examined.
    "year_to_date_rate", -- For the Performance Metric and the Quarter being examined, this is the rate of the metric as calculated by dividing the Year to Date Numerator by the Year to Date Denominator.
    "rate", -- For the Age Group, OMH Region, Performance Metric and Quarter being examined, this is the rate of the metric as calculated by dividing the Numerator by the Denominator.
    "numerator" -- Value of the "top" of the "Rate" calculation for the Age Group, OMH Region, Performance Metric and Quarter that is being examined. For Detailed Descriptions of the Numerator for each metric, see the “Detailed Metric Definitions” in the data dictionary attached to this dataset.
FROM
    "ny-gov/bho-medication-fill-data-20102014-cc9j-4ujx:latest"."bho_medication_fill_data_20102014"
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 ny-gov/bho-medication-fill-data-20102014-cc9j-4ujx with SQL in under 60 seconds.

This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.ny.gov. When you queryny-gov/bho-medication-fill-data-20102014-cc9j-4ujx: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.ny.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 \
  "ny-gov/bho-medication-fill-data-20102014-cc9j-4ujx" \
  --handler-options '{
    "domain": "data.ny.gov",
    "tables": {
        "bho_medication_fill_data_20102014": "cc9j-4ujx"
    }
}'

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, ny-gov/bho-medication-fill-data-20102014-cc9j-4ujx is just another Postgres schema.