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 firerescue_inspections table in this repository, by referencing it like:
"norfolk-gov/firerescue-inspections-jf3j-u4s7:latest"."firerescue_inspections"or in a full query, like:
SELECT
":id", -- Socrata column ID
"street_prefix", -- North, South, East or West
"latitude", -- Latitude coordinates
"apartment_room", -- Apartment or building unit
"inspection_id", -- Specific Fire-Rescue identifier for each individual inspection
"inspection_description", -- Description of the inspection
"inspection_time", -- Time of inspection
"district", -- Fire Battalion District
"street_suffix", -- Extension
"aes_type", -- Automatic Extinguishing System type
"address_number", -- Street number
"detector_presence", -- Firehouse (Fire Rescue system of record) description to indicate the presence of a smoke detector
"violation_id", -- Specific Fire-Rescue identifier for each individual violation
"reinspection_number", -- How many times the property has been reinspected
"gpin", -- Grid Parcel Identification Number generated to provide a unique identifier for each parcel
"violation_code", -- Statewide Fire Prevention Violation Code
"roof_cover", -- NFIRS description assigned to roof cover
"inspection_completed_date", -- Date of completed inspection
"violation_description", -- Description of the violation
"address_2", -- Additional information about location
"mixed_use", -- NFIRS description assigned to properties with mixed use purposes
"aes_presence", -- Automatic Extinguishing System present
"reinspection", -- Does the property require reinspection - Y or N?
"count", -- How many times an inspector returned to assess the violation from original inspection
"variance_date", -- The date a variance was granted
"detector_power_supply", -- NFIRs description that denotes the type of power source
"floors_below", -- Number of basement levels below grade plane
"floors_above", -- Number of stories above grade plane
"station", -- The Norfolk Fire Station number that serves this area
"detector_type", -- NFIRS description to denote the type of smoke detector
"longitude", -- Longitude coordinates
"street", -- Name of street
"structure_type", -- NFIRs description that denotes building type
"name", -- Name of business
"violation_reported_date", -- Date violation was reported
"repaired_date", -- Date the violation was repaired
"property_ownership", -- NFIRS description of the property ownership
"inspection_scheduled_date", -- Date of scheduled inspection
"occupation_id", -- Specific Fire-Rescue identifier for a specific structure
"street_type", -- A component that qualifies the street name by type of street such as AVE(Avenue), DR (Drive), or RD (Road)
"zip_code", -- Zip code
"property_use_description", -- National Fire Incident Reporting System (NFIRS) Property use description
"building_status" -- NFIRS description that denotes building status
FROM
"norfolk-gov/firerescue-inspections-jf3j-u4s7:latest"."firerescue_inspections"
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 norfolk-gov/firerescue-inspections-jf3j-u4s7 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 norfolk-gov/firerescue-inspections-jf3j-u4s7: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 norfolk-gov/firerescue-inspections-jf3j-u4s7Checkout 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 norfolk-gov/firerescue-inspections-jf3j-u4s7:latestThis will download all the objects for the latest tag of norfolk-gov/firerescue-inspections-jf3j-u4s7 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 norfolk-gov/firerescue-inspections-jf3j-u4s7: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 norfolk-gov/firerescue-inspections-jf3j-u4s7: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, norfolk-gov/firerescue-inspections-jf3j-u4s7 is just another Postgres schema.