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 dsny_donatenyc_directory table in this repository, by referencing it like:
"cityofnewyork-us/dsny-donatenyc-directory-gkgs-za6m:latest"."dsny_donatenyc_directory"or in a full query, like:
SELECT
":id", -- Socrata column ID
"bin", -- Building Identification Number (BIN). A seven-digit numerical identifier unique to each building in the City of New York.
"latitude", -- Latitude of site for mapping purposes.
"police_precinct", -- Police precinct in which the site is located.
"community_district", -- Borough and Community District which is represented by a single-digit borough number followed by two-digit borough community district number.
"dsny_section", -- Sections are subdivisions of DSNY Districts.
"website", -- Website for site listed in Donate Directory, if available.
"site", -- Name of site in Donate Directory.
"ntaname", -- Neighborhood Tabulation Area Name. Neighborhood Tabulation Areas are small area boundaries that were initially created by the Department of City Planning for small area population projections. However, NTAs are now being used to present data from the Decennial Census and American Community Survey.
"senate_district", -- New York City area State Senate District name.
"councildist", -- NYC Council District Number. There are 51 Council districts throughout the five boroughs and each one is represented by an elected Council Member.
"congressional_district", -- New York City area Congressional District name.
"phone", -- Contact phone number for site listed in Donate Directory, if available.
"point_1", -- Longitude and Latitude formatted for map "pin"
"dsny_zone", -- Zone abbreviation as defined by DSNY
"longitude", -- Longitude of site for mapping purposes.
"bbl", -- Ten digit Borough-Block-Lot (BBL) or parcel numbers that identify the location of buildings or properties.
"census_tract", -- Decennial census tracts of 2020. The naming convention follows NYC's standard; merged string of borough code and 2020 census tract number.
"hours", -- Open hours for site listed in the Donate Directory.
"categoriesavailable", -- Categories of donations that are available from the site.
"assembly_district", -- New York City area Assembly District name.
"pickupstatus", -- Indicates whether a site listed in the Donate Directory is a pickup site.
"objectid", -- ObjectIDs are sequential, non-null integers serving as primary keys for the database to read. However, these should not be used as primary identifiers by users as the sequential numbers are subject to change during updates.
"email", -- Contact email address for site listed in Donate Directory, if available.
"address", -- Street address associated with site.
"borocd", -- Borough and Community District which is represented by a single-digit borough number followed by two-digit borough community district number.
"dsny_district", -- District abbreviation as defined by DSNY
"partnerstatus", -- Indicates whether a site listed in the Donate Directory is a Donate partner.
"additionalmaterialinformation", -- Lists additional information about the site.
"categoriesaccepted", -- Categories of donations that are accepted by the site.
"borough", -- On of the five borough of NYC: Bronx, Brooklyn, Manhattan, Queens, and Staten Island.
":@computed_region_f5dn_yrer", -- This column was automatically created in order to record in what polygon from the dataset 'Community Districts' (f5dn-yrer) the point in column 'point_1' is located. This enables the creation of region maps (choropleths) in the visualization canvas and data lens.
":@computed_region_efsh_h5xi", -- This column was automatically created in order to record in what polygon from the dataset 'Zip Codes' (efsh-h5xi) the point in column 'point_1' is located. This enables the creation of region maps (choropleths) in the visualization canvas and data lens.
":@computed_region_sbqj_enih", -- This column was automatically created in order to record in what polygon from the dataset 'Police Precincts' (sbqj-enih) the point in column 'point_1' is located. This enables the creation of region maps (choropleths) in the visualization canvas and data lens.
":@computed_region_92fq_4b7q", -- This column was automatically created in order to record in what polygon from the dataset 'City Council Districts' (92fq-4b7q) the point in column 'point_1' is located. This enables the creation of region maps (choropleths) in the visualization canvas and data lens.
":@computed_region_yeji_bk3q" -- This column was automatically created in order to record in what polygon from the dataset 'Borough Boundaries' (yeji-bk3q) the point in column 'point_1' is located. This enables the creation of region maps (choropleths) in the visualization canvas and data lens.
FROM
"cityofnewyork-us/dsny-donatenyc-directory-gkgs-za6m:latest"."dsny_donatenyc_directory"
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/dsny-donatenyc-directory-gkgs-za6m with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.cityofnewyork.us. When you querycityofnewyork-us/dsny-donatenyc-directory-gkgs-za6m: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)"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 (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.cityofnewyork.us, 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 \
"cityofnewyork-us/dsny-donatenyc-directory-gkgs-za6m" \
--handler-options '{
"domain": "data.cityofnewyork.us",
"tables": {
"dsny_donatenyc_directory": "gkgs-za6m"
}
}'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, cityofnewyork-us/dsny-donatenyc-directory-gkgs-za6m is just another Postgres schema.