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 waofm_april_1_population_by_state_county_and_city table in this repository, by referencing it like:
"wa-gov/waofm-april-1-population-by-state-county-and-city-2hia-rqet:latest"."waofm_april_1_population_by_state_county_and_city"or in a full query, like:
SELECT
":id", -- Socrata column ID
"pop_2000", -- 2000 Census Population Census Base
"pop_2018", -- 2018 Intercensal Population Estimate
"pop_2004", -- 2004 Intercensal Population Estimate
"pop_2019", -- 2019 Intercensal Population Estimate
"pop_2023", -- 2023 Postcensal Population Estimate
"pop_2001", -- 2001 Intercensal Population Estimate
"pop_2016", -- 2016 Intercensal Population Estimate
"pop_2017", -- 2017 Intercensal Population Estimate
"pop_2003", -- 2003 Intercensal Population Estimate
"pop_2005", -- 2005 Intercensal Population Estimate
"pop_2006", -- 2006 Intercensal Population Estimate
"pop_2024", -- 2024 Postcensal Population Estimate
"sequence", -- Sequence number (use this field to return the table to the original sort order)
"pop_1996", -- 1996 Intercensal Population Estimate
"pop_2008", -- 2008 Intercensal Population Estimate
"pop_1995", -- 1995 Intercensal Population Estimate
"pop_2009", -- 2009 Intercensal Population Estimate
"pop_2010", -- 2010 Census Population Census Base
"pop_1994", -- 1994 Intercensal Population Estimate
"pop_2011", -- 2011 Intercensal Population Estimate
"pop_2013", -- 2013 Intercensal Population Estimate
"pop_1993", -- 1993 Intercensal Population Estimate
"pop_1990", -- 1990 Census Population Census Base
"jurisdiction", -- Jurisdiction (state, county, city, incorporated area, or unincorporated area)
"pop_2014", -- 2014 Intercensal Population Estimate
"county", -- County name
"pop_1992", -- 1992 Intercensal Population Estimate
"pop_2021", -- 2021 Postcensal Population Estimate
"pop_2007", -- 2007 Intercensal Population Estimate
"pop_2015", -- 2015 Intercensal Population Estimate
"pop_2002", -- 2002 Intercensal Population Estimate
"pop_2012", -- 2012 Intercensal Population Estimate
"pop_1998", -- 1998 Intercensal Population Estimate
"pop_2020", -- 2020 Census Population Census Base
"pop_1991", -- 1991 Intercensal Population Estimate
"pop_1999", -- 1999 Intercensal Population Estimate
"pop_1997", -- 1997 Intercensal Population Estimate
"filter", -- Filter (use this field to filter the data by geography: 1=county or state, 2=unincorporated county or state, 3=incorporated county or state, 4=city )
"pop_2022" -- 2022 Postcensal Population Estimate
FROM
"wa-gov/waofm-april-1-population-by-state-county-and-city-2hia-rqet:latest"."waofm_april_1_population_by_state_county_and_city"
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 wa-gov/waofm-april-1-population-by-state-county-and-city-2hia-rqet 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 wa-gov/waofm-april-1-population-by-state-county-and-city-2hia-rqet: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 wa-gov/waofm-april-1-population-by-state-county-and-city-2hia-rqetCheckout 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 wa-gov/waofm-april-1-population-by-state-county-and-city-2hia-rqet:latestThis will download all the objects for the latest tag of wa-gov/waofm-april-1-population-by-state-county-and-city-2hia-rqet 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 wa-gov/waofm-april-1-population-by-state-county-and-city-2hia-rqet: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 wa-gov/waofm-april-1-population-by-state-county-and-city-2hia-rqet: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, wa-gov/waofm-april-1-population-by-state-county-and-city-2hia-rqet is just another Postgres schema.