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 311_service_requests_mygnv table in this repository, by referencing it like:
"cityofgainesville/311-service-requests-mygnv-78uv-94ar:latest"."311_service_requests_mygnv"or in a full query, like:
SELECT
":id", -- Socrata column ID
"created", -- The date and time the service request was made
":@computed_region_4rat_gsiv",
"description", -- Detailed description of the service request
":@computed_region_u9vc_vmbc",
":@computed_region_ndi2_bfht",
"commission_district",
"status", -- Status of the request. OPEN: The request has been sent ACKNOWLEDGED: Staff has acknowledged that the request has been opened. CLOSED: The service request has either been made into a work order to fix the problem or the request has been resolved with the requester. REOPENED: The request has been reopened by the requester for further investigation
":@computed_region_axii_i744",
"longitude",
"location",
":@computed_region_43jd_v64e",
":@computed_region_9cfm_spy5",
"location_detail", -- The address of the issue (manually input by the requester)
"reporter_display", -- The chosen display name for those reporting. May be a user name (logged in an using their user name to report), anonymous (logged in but choosing to stay anonymous) or guest (not signed in)
"reported_using_mobile", -- If the issue was reported through a mobile device
"days_to_close",
"assigned_to", -- The department or office the request has been assigned to
"last_updated", -- The date and time of the last update made to the service request
"request_type",
"latitude",
"police_sector",
"reopened", -- The date and time of when the service request was reopened by the requester
"closed", -- The date and time of when the service request was "closed" by staff. This reflects whether the request was moved into a work order to solve the issue or if the ticket was resolved with the requester
"acknowledged", -- The date and time of when the service request was acknowledged by staff through the online 311 system
"minutes_to_acknowledge", -- The amount of time (in minutes) to acknowledge the open request with a message through the online 311 system
"minutes_to_close", -- The amount of time (in minutes) to resolve the request with a message through the online 311 system
"id", -- The unique identification number for each open service request
":@computed_region_qsqf_gz5q"
FROM
"cityofgainesville/311-service-requests-mygnv-78uv-94ar:latest"."311_service_requests_mygnv"
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 cityofgainesville/311-service-requests-mygnv-78uv-94ar 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 cityofgainesville/311-service-requests-mygnv-78uv-94ar: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 cityofgainesville/311-service-requests-mygnv-78uv-94arCheckout 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 cityofgainesville/311-service-requests-mygnv-78uv-94ar:latestThis will download all the objects for the latest tag of cityofgainesville/311-service-requests-mygnv-78uv-94ar 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 cityofgainesville/311-service-requests-mygnv-78uv-94ar: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 cityofgainesville/311-service-requests-mygnv-78uv-94ar: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, cityofgainesville/311-service-requests-mygnv-78uv-94ar is just another Postgres schema.