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 public_cemetery_locations table in this repository, by referencing it like:
"ny-gov/public-cemetery-locations-bvve-d2q8:latest"."public_cemetery_locations"or in a full query, like:
SELECT
":id", -- Socrata column ID
"citytowntype", -- Type of municipality specified by CityTownMuniCode.
"longitude", -- Longitude of location in decimal degrees. Blank if map location is not specified for this location.
"villagemunicode", -- Unique identifier of the village jurisdiction within which cemetery is located, if it is located within an incorporated village. The identifier is the 12-digit local government entity identifier assigned to the village by the Office of State Comptroller (see https://osc.state.ny.us/localgov/datanstat/entitytable.htm). Blank if unknown or cemetery is not located within a village.
"swis", -- StateWide Information System code for jurisdiction which contains the tax parcel associated with this location. Blank if the coordinates of the location were not matched to a nearby cemetery tax parcel by the division.
"citytownmunicode", -- Unique identifier of the city or town jurisdiction within which cemetery is located. The identifier is the 12-digit local government entity identifier assigned to the town by the Office of State Comptroller (see https://osc.state.ny.us/localgov/datanstat/entitytable.htm). Blank if not known or cemetery is located within any such incorporated jurisdiction.
"citytownname", -- Name of city or town jurisdiction specified by CityTownMuniCode.
"cemeteryname", -- Name of the cemetery corporation.
"taxparcel", -- Standardized Section, Block, Lot key for tax parcel associated with this location. Blank if the coordinates of the location were not matched to a nearby cemetery tax parcel by the division.
"villagename", -- Name of village specified by VillageMuniCode
":@computed_region_kjdx_g34t", -- This column was automatically created in order to record in what polygon from the dataset 'Counties' (kjdx-g34t) the point in column 'georeference' is located. This enables the creation of region maps (choropleths) in the visualization canvas and data lens.
":@computed_region_wbg7_3whc", -- This column was automatically created in order to record in what polygon from the dataset 'New York Zip Codes' (wbg7-3whc) the point in column 'georeference' is located. This enables the creation of region maps (choropleths) in the visualization canvas and data lens.
":@computed_region_yamh_8v7k", -- This column was automatically created in order to record in what polygon from the dataset 'NYS Municipal Boundaries' (yamh-8v7k) the point in column 'georeference' is located. This enables the creation of region maps (choropleths) in the visualization canvas and data lens.
"mailingaddressstreet", -- Street address for location.
"cemid", -- Unique five-digit identifier for cemetery associated with this location issued by the Division of Cemeteries.
"georeference", -- Open Data/Socrata-generated geocoding information from supplied address components.
"latitude" -- Latitude of location in decimal degrees. Blank if map location is not specified for this location.
FROM
"ny-gov/public-cemetery-locations-bvve-d2q8:latest"."public_cemetery_locations"
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 ny-gov/public-cemetery-locations-bvve-d2q8 with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.ny.gov. When you queryny-gov/public-cemetery-locations-bvve-d2q8: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.ny.gov, 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 \
"ny-gov/public-cemetery-locations-bvve-d2q8" \
--handler-options '{
"domain": "data.ny.gov",
"tables": {
"public_cemetery_locations": "bvve-d2q8"
}
}'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, ny-gov/public-cemetery-locations-bvve-d2q8 is just another Postgres schema.