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 njsp_traffic_stop_data_2015 table in this repository, by referencing it like:
"nj-gov/njsp-traffic-stop-data-2015-j2rb-g65t:latest"."njsp_traffic_stop_data_2015"or in a full query, like:
SELECT
":id", -- Socrata column ID
"stationname", -- Name of the Station where the stop occurred
"totalparaphrenalia", -- Total number of persons charged with a paraphernalia charge
"movingwarning", -- Whether the stop resulted in a moving warning
"reportingperiod", -- OLEPS reporting period
"arrest", -- Whether the stop included an arrest
"totalwarnings", -- Total number of warnings
"poststopinteraction", -- Whether the stop included any post-stop interaction or activity
"troopname", -- Name of the Troop where the stop occurred
"year", -- Year when the stop occurred
"nonmovingwarning", -- Whether the stop resulted in a non-moving warning
"vehiclesearch", -- Whether the stop included a search of a vehicle
"evidenceseizure", -- Whether the stop included an evidence seizure
"totalpersonsinteractedwith", -- Total number of persons the trooper interacted with
"totalwantedpersons", -- Total number of persons identified as a wanted person, having a charge of 2C: 29-9
"totaldwi", -- Total number of persons charged with DWI
"totalothercharges", -- Total number of persons charged with a charge other than those specified
"totalpersonsarrested", -- Total number of persons arrested
"totalweapons", -- Total number of persons charged with a weapons related charge
"personsearch", -- Whether the stop included a search of a person
"id", -- Unique ID for each stop
"movingsummons", -- Whether the stop resulted in a moving summons
"nonmovingsummons", -- Whether the stop resulted in a non-moving summons
"statutenumber", -- Statute listed as the reason of the stop
"movingflag", -- Whether the reason statute is a moving violation
"driverrace", -- Driver Race
"exit", -- Whether the stop included a driver or passenger vehicle exit
"frisk", -- Whether the stop included a frisk
"consentrequest", -- Whether the stop included a request for consent to search
"useofforce", -- Whether the stop included a use of force
"k9", -- Whether the stop included a K-9 Deployment
"totalarrestednotcharged", -- Total number of persons arrested, but not charged with a specific statute or crime
"totalarrestedcharged", -- Total number of persons arrested and charged with a specific statue or crime
"totalobstruction", -- Total number of persons charged with Obstruction
"totalpossession", -- Total number of persons charged with a possession of CDS charge
"month", -- Month when the stop occurred
"totalsummons", -- Total number of summonses
"stopoutcome", -- Coded Outcome of the stop
"statutename" -- Name of the statute listed as the reason for the stop
FROM
"nj-gov/njsp-traffic-stop-data-2015-j2rb-g65t:latest"."njsp_traffic_stop_data_2015"
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 nj-gov/njsp-traffic-stop-data-2015-j2rb-g65t 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 nj-gov/njsp-traffic-stop-data-2015-j2rb-g65t: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 nj-gov/njsp-traffic-stop-data-2015-j2rb-g65tCheckout 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 nj-gov/njsp-traffic-stop-data-2015-j2rb-g65t:latestThis will download all the objects for the latest tag of nj-gov/njsp-traffic-stop-data-2015-j2rb-g65t 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 nj-gov/njsp-traffic-stop-data-2015-j2rb-g65t: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 nj-gov/njsp-traffic-stop-data-2015-j2rb-g65t: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, nj-gov/njsp-traffic-stop-data-2015-j2rb-g65t is just another Postgres schema.