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 radon_test_results_september_1986_current_annual table in this repository, by referencing it like:
"pa-gov/radon-test-results-september-1986-current-annual-vkjb-sx3k:latest"."radon_test_results_september_1986_current_annual"or in a full query, like:
SELECT
":id", -- Socrata column ID
"mitigation_system_indicator", -- Specify the type of Mitigation System
"radon_test_result_identifier", -- The unique identifier assigned for each Radon Test Result.
"county_code", -- The code that represents the county.
"test_method_type_code", -- Identifier of the type or category of method.
"state_code", -- A code designation used to identify a principal administrative subdivision of the United States, Canada, or Mexico
"address_postal_code", -- The combination of the 5-digit Zone Improvement Plan (ZIP) code and the four-digit extension code (if available) that represents the geographic segment that is a subunit of the ZIP Code, assigned by the U.S. Postal Service to a geographic location to facilitate mail delivery; or the postal zone specific to the country, other than the U.S., where the mail is delivered.
"radon_data_identifier", -- A unique identifier for each Radon Test Result.
"test_end_date", -- End Date of the Radon Test.
"measure_value", -- The recorded dimension, capacity, quality, or amount of something ascertained by measuring or observing.
"building_type_code", -- The designator that represents the Type of the building purpose.
"radon_data_source_name", -- The data source where the test data is retrieved.
"municipality_name", -- The name of the municipality.
"test_start_date", -- Start Date of the Radon Test.
"building_purpose_code", -- The designator that represents the building purpose.
"census_tract", -- This is a 11 character code known maintained by the US Census Bureau known as the 'Census Code'. It's last 6 characters is the true federally acceptable 'Census Tract' number. This field identifies a particular tract using an 11-digit code consisting of a 2- digit code for the state, a 3-digit code for the county (either of which may include one or more "leading" zeros), and 6 digits for the census tract (including any leading zeros, and also two zeros in the many cases in which the basic tract code has no suffix). Census Tract was a new column added to the national schema definition by CDC in 2017, due to the sensitivity of the actual location address information. It is more granular than zip code and the most detailed test result location permitted due to address confidentiality requirements.
"county_name", -- A name used to identify a primary geopolitical unit of the world.
"test_floor_level_text", -- The floor level in the building where the Radon test was conducted.
"building_sub_type_code" -- The designator that represents the Sub-Type of the building purpose.
FROM
"pa-gov/radon-test-results-september-1986-current-annual-vkjb-sx3k:latest"."radon_test_results_september_1986_current_annual"
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/radon-test-results-september-1986-current-annual-vkjb-sx3k with SQL in under 60 seconds.
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, 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 (like this repository), where the author has pushed Splitgraph Images to the repository, you can "clone" and/or "checkout" the data using sgr cloneand sgr checkout.
Cloning Data
Because pa-gov/radon-test-results-september-1986-current-annual-vkjb-sx3k:latest is a Splitgraph Image, you can clone the data from Spltgraph Cloud to your local engine, where you can query it like any other Postgres database, using any of your existing tools.
First, install Splitgraph if you haven't already.
Clone the metadata with sgr clone
This will be quick, and does not download the actual data.
sgr clone pa-gov/radon-test-results-september-1986-current-annual-vkjb-sx3kCheckout the data
Once you've cloned the data, you need to "checkout" the tag that you want. For example, to checkout the latest tag:
sgr checkout pa-gov/radon-test-results-september-1986-current-annual-vkjb-sx3k:latestThis will download all the objects for the latest tag of pa-gov/radon-test-results-september-1986-current-annual-vkjb-sx3k and load them into the Splitgraph Engine. Depending on your connection speed and the size of the data, you will need to wait for the checkout to complete. Once it's complete, you will be able to query the data like you would any other Postgres database.
Alternatively, use "layered checkout" to avoid downloading all the data
The data in pa-gov/radon-test-results-september-1986-current-annual-vkjb-sx3k:latest is 0 bytes. If this is too big to download all at once, or perhaps you only need to query a subset of it, you can use a layered checkout.:
sgr checkout --layered pa-gov/radon-test-results-september-1986-current-annual-vkjb-sx3k:latestThis will not download all the data, but it will create a schema comprised of foreign tables, that you can query as you would any other data. Splitgraph will lazily download the required objects as you query the data. In some cases, this might be faster or more efficient than a regular checkout.
Read the layered querying documentation to learn about when and why you might want to use layered queries.
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/radon-test-results-september-1986-current-annual-vkjb-sx3k is just another Postgres schema.