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 numbers_and_rates_of_substancerelated_fatalities table in this repository, by referencing it like:
"novascotia-ca/numbers-and-rates-of-substancerelated-fatalities-iu6y-z4n3:latest"."numbers_and_rates_of_substancerelated_fatalities"or in a full query, like:
SELECT
":id", -- Socrata column ID
"living_situation", -- Living situation of decedent at time of death
"manner_of_death", -- Manner of death refers to the mode of method of death and is classified as one of five manners: natural; accident; suicide; homicide; undetermined (https://nslegislature.ca/sites/default/files/legc/statutes/fatality%20investigations.pdf). Acute toxicity deaths are not classified as natural in manner and therefore this dataset excludes deaths for which manner was classified as natural. Data are presented for manners suicide and accident.
"percent", -- Percent of cases in that year with that characteristic
"frequency", -- Number of deaths reported and investigated by NSMES, confirmed and probable toxicity deaths
"year_month", -- Year and month of death or when individual was found dead
"quarter", -- Quarter in which individual died or was found dead. Q1 = Jan-Mar; Q2 = Apr-Jun; Q3 = Jul-Sep; Q4 Oct-Dec.
"others_present_aware", -- Describes whether contextual information available suggests others were present or aware that decedent was using substances prior to death
"drug_type", -- Type of substance contributing to toxicity death
"month", -- Month of death or month individual was found dead
"year", -- Year of death or year individual was found dead
"place_of_event", -- Place of toxicity event
"rate_per_100_000_population_annualized_for_quarterly_data", -- Number of cases per 100,000 population using Statistics Canada census population estimates; Crude rate per 100,000 population
"opioids_stimulants_other", -- Describes whether the drugs that contributed to the toxicity death as certified in the cause of death statement belonged to drug class opioids or stimulants (or both or neither)
"sex", -- Sex
"health_zone_of_residence" -- Health zone of residence
FROM
"novascotia-ca/numbers-and-rates-of-substancerelated-fatalities-iu6y-z4n3:latest"."numbers_and_rates_of_substancerelated_fatalities"
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 novascotia-ca/numbers-and-rates-of-substancerelated-fatalities-iu6y-z4n3 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 novascotia-ca/numbers-and-rates-of-substancerelated-fatalities-iu6y-z4n3: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 novascotia-ca/numbers-and-rates-of-substancerelated-fatalities-iu6y-z4n3Checkout 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 novascotia-ca/numbers-and-rates-of-substancerelated-fatalities-iu6y-z4n3:latestThis will download all the objects for the latest tag of novascotia-ca/numbers-and-rates-of-substancerelated-fatalities-iu6y-z4n3 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 novascotia-ca/numbers-and-rates-of-substancerelated-fatalities-iu6y-z4n3: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 novascotia-ca/numbers-and-rates-of-substancerelated-fatalities-iu6y-z4n3: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, novascotia-ca/numbers-and-rates-of-substancerelated-fatalities-iu6y-z4n3 is just another Postgres schema.