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 housing_maintenance_code_violations table in this repository, by referencing it like:
"cityofnewyork-us/housing-maintenance-code-violations-wvxf-dwi5:latest"."housing_maintenance_code_violations"or in a full query, like:
SELECT
":id", -- Socrata column ID
"approveddate", -- Date when violation was approved
"boroid", -- unique number to identify borough
"violationstatus", -- Status of Violation(Open / Close)
"registrationid", -- Unique identifier of valid registration information
"censustract", -- The US census tract associated with the provided entity location (in the format of up to four-digit integers, followed by an optional two-digit suffix; e.g., “15.02” or “319”).
"currentstatusdate", -- Date when the current status when into effect
"story", -- Floor of violation
"novid", -- Unique identifier of the Notice of Violation sent to the owner
"newcertifybydate", -- Modified date by when the owner was to inform HPD that the violation as corrected
"streetname", -- Address information for the building
"housenumber", -- Address information for the building
"lowhousenumber", -- Address information for the building
"streetcode", -- Address information for the building
"ordernumber", -- Reference to the abstract description of the violation condition which cites a specific section of the law which is in violation
"novdescription", -- Description of the violation
"communityboard", -- The NYC community board associated with the provided entity location (numbered 1 – 59.
"bbl", -- The Borough, Block, Lot (BBL) associated with the provided entity location. It is formatted as a ten-digit numerical identifier, which is unique to each parcel of real property in NYC.
"currentstatusid", -- unique id to identify current status
"originalcorrectbydate", -- Original date by when the owner was to correct the violation
"currentstatus", -- Violation status (see below for details)
"violationid", -- Unique identifier of Violation
"zip", -- Address information for the building
"apartment", -- Apartment with violation, if applicable
"block", -- Tax block for building
"lot", -- Tax lot for building
"councildistrict", -- The NYC council district associated with the provided entity location (numbered 1 – 51).
"inspectiondate", -- Date when the violation was observed
"longitude", -- The longitude associated with the provided entity location.
"rentimpairing", -- A rent-impairing violation is a condition within a multiple dwelling which constitutes, or if not promptly corrected will constitute, a fire hazard or a serious threat to the life, health or safety of occupants thereof (New York State Multiple Dwelling Law Section 302).
"originalcertifybydate", -- Original date by when the owner was to inform HPD that the violation as corrected
"newcorrectbydate", -- Modified date by when the owner was to correct the violation
"buildingid", -- Unique identifier of building
"boro", -- Boro code (1 = Manhattan, 2 = Bronx, 3 = Brooklyn, 4 = Queens, 5 = Staten Island)
"certifieddate", -- Date when the violation was certified (if it was)
"novissueddate", -- Date when the NOV was sent
"latitude", -- The latitude associated with the provided entity location.
"highhousenumber", -- Address information for the building
"bin", -- The Building Identification Number (BIN) associated with the provided entity location. It is formatted as a seven-digit numerical identifier, which is unique to each building in NYC.
"class", -- Indicator of seriousness of the violations, where A is the least serious and C is the most serious
"novtype", -- Original / Reissued Notice of Violation. For more information on the Reissuance process, see http://www1.nyc.gov/site/hpd/owners/compliance-clear-violations.page .
"nta" -- The Neighborhood Tabulation Area (NTA) associated with the provided entity location, which is formatted as a two-letter borough identifier followed by a two-digit numerical identifier (e.g., “BX31”).
FROM
"cityofnewyork-us/housing-maintenance-code-violations-wvxf-dwi5:latest"."housing_maintenance_code_violations"
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/housing-maintenance-code-violations-wvxf-dwi5 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/housing-maintenance-code-violations-wvxf-dwi5: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/housing-maintenance-code-violations-wvxf-dwi5" \
--handler-options '{
"domain": "data.cityofnewyork.us",
"tables": {
"housing_maintenance_code_violations": "wvxf-dwi5"
}
}'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/housing-maintenance-code-violations-wvxf-dwi5 is just another Postgres schema.