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
"highhousenumber", -- Address information for the building
"buildingid", -- Unique identifier of building
"novid", -- Unique identifier of the Notice of Violation sent to the owner
"currentstatusid", -- unique id to identify current status
"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”).
"councildistrict", -- The NYC council district associated with the provided entity location (numbered 1 – 51).
"apartment", -- Apartment with violation, if applicable
"novdescription", -- Description of the violation
"housenumber", -- Address information for the building
"newcertifybydate", -- Modified date by when the owner was to inform HPD that the violation as corrected
"story", -- Floor of violation
"registrationid", -- Unique identifier of valid registration information
"violationstatus", -- Status of Violation(Open / Close)
"streetname", -- Address information for the building
"lowhousenumber", -- Address information for the building
"boroid", -- unique number to identify borough
"boro", -- Boro code (1 = Manhattan, 2 = Bronx, 3 = Brooklyn, 4 = Queens, 5 = Staten Island)
"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).
"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 .
"class", -- Indicator of seriousness of the violations, where A is the least serious and C is the most serious
"currentstatus", -- Violation status (see below for details)
"violationid", -- Unique identifier of Violation
"zip", -- Address information for the building
"block", -- Tax block for building
"lot", -- Tax lot for building
"originalcorrectbydate", -- Original date by when the owner was to correct the violation
"inspectiondate", -- Date when the violation was observed
"approveddate", -- Date when violation was approved
"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
"certifieddate", -- Date when the violation was certified (if it was)
"novissueddate", -- Date when the NOV was sent
"streetcode", -- Address information for the building
"latitude", -- The latitude associated with the provided entity location.
"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”).
"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.
"longitude", -- The longitude associated with the provided entity location.
"communityboard", -- The NYC community board associated with the provided entity location (numbered 1 – 59.
"currentstatusdate", -- Date when the current status when into effect
"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.
"ordernumber" -- Reference to the abstract description of the violation condition which cites a specific section of the law which is in violation
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.
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/housing-maintenance-code-violations-wvxf-dwi5: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/housing-maintenance-code-violations-wvxf-dwi5Checkout 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/housing-maintenance-code-violations-wvxf-dwi5:latestThis will download all the objects for the latest tag of cityofnewyork-us/housing-maintenance-code-violations-wvxf-dwi5 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/housing-maintenance-code-violations-wvxf-dwi5: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/housing-maintenance-code-violations-wvxf-dwi5: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/housing-maintenance-code-violations-wvxf-dwi5 is just another Postgres schema.