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 verified_locations_for_nyc_cityfunded_social table in this repository, by referencing it like:
"cityofnewyork-us/verified-locations-for-nyc-cityfunded-social-922w-z7da:latest"."verified_locations_for_nyc_cityfunded_social"or in a full query, like:
SELECT
":id", -- Socrata column ID
"census_tract", -- The census tract for the site location.
"site_intersection_street_2", -- The second street of an intersection if services are provided at an intersection.
"community_board", -- The community district for the location.
"longitude", -- X coordinate of location expressed in decimal degrees in WGS84 datum.
"latitude", -- Y coordinate of location expressed in decimal degrees in WGS84 datum.
"street_name", -- The street name of the address.
"street_number", -- The street number of the address.
"city", -- The city in which the address is located.
"address_2", -- (Deprecated) A second (additional) line of address information. (This field is deprecated: we recommend including all address information before 'city' as a comma separated list in address_1. There is no guarantee that systems will read this line of address information.)
"postcode", -- The postal code for the address.
"address_1", -- The first line(s) of the address, including office, building number and street.
"physical_address_id", -- Each physical address must have a unique identifier.
"borough", -- The borough in which the address is located.
"state_province", -- The state or province in which the address is located.
"council_district", -- The city council district for the location.
"site_catchment", -- The service area if no address available.
"location_id", -- The identifier of the location for which this is the address.
"site_intersection_street_1", -- The first street of an intersection if services are provided at an intersection.
"nta", -- The Neighborhood Tabulation Area for the site location.
"bbl", -- The borough-block-lot where the site is located.
"bin" -- The building identification number for the location.
FROM
"cityofnewyork-us/verified-locations-for-nyc-cityfunded-social-922w-z7da:latest"."verified_locations_for_nyc_cityfunded_social"
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 cityofnewyork-us/verified-locations-for-nyc-cityfunded-social-922w-z7da 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 cityofnewyork-us/verified-locations-for-nyc-cityfunded-social-922w-z7da: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 cityofnewyork-us/verified-locations-for-nyc-cityfunded-social-922w-z7daCheckout 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 cityofnewyork-us/verified-locations-for-nyc-cityfunded-social-922w-z7da:latestThis will download all the objects for the latest tag of cityofnewyork-us/verified-locations-for-nyc-cityfunded-social-922w-z7da 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 cityofnewyork-us/verified-locations-for-nyc-cityfunded-social-922w-z7da: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 cityofnewyork-us/verified-locations-for-nyc-cityfunded-social-922w-z7da: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, cityofnewyork-us/verified-locations-for-nyc-cityfunded-social-922w-z7da is just another Postgres schema.