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_explorer table in this repository, by referencing it like:
"edmonton-ca/311-explorer-ukww-xkmj:latest"."311_explorer"or in a full query, like:
SELECT
":id", -- Socrata column ID
"location", -- Spatial coordinates for the location of the issue that has been identified.
"status_detail", -- Certain request types may include additional details describing the progress or action associated with the request.
"ticket_created_date_time", -- The date the service request was submitted.
"ticket_id", -- The unique identifier (number) for the service request.
"issue_description", -- Provides a general description of the service request.
"street_address", -- The location of the service request.
"ivara_ticket_num",
"posse_number", -- Unique Identifier generated by POSSE
"long", -- Vertical Geographic Coordinate
"ticket_source", -- The channel or method in which the service request was initiated. Examples will include telephone, 311 app or email.
"transit_ref_number", -- A ticket number from any Transit application
"community_league", -- The Community League associated with the location of the service. (If applicable)
"ticket_closed_date_time", -- The date the service request was acted upon. The appropriate City department has investigated the concern and identified steps to resolve your request. Action for resolving the issue may be deferred as work may be dependent on priority and weather conditions or your issue has been closed due to lack of information including contact details. (311 Explorer version)
"location_address",
"location_zip",
"display_name", -- The City neighbourhood where the service request is located.
"agency_responsible", -- The business area that is responsible for the service (311 Explorer version).
"lat", -- Horizontal Geographic Coordinate
"neighborhood_district", -- The City Ward associated with the location.
"issue_type", -- The type of activity or service request.
"calendar_year", -- Year when Service Ticket was created.
"ticket_status", -- Status of the request. It can be either Open or Closed. Open means the service request has been received and assigned to the appropriate City area for review and action. Response times can be dependent on several factors including weather conditions, availability of resources and assessed priority of the work required. Closed means the appropriate City area has investigated your concern and has taken the necessary action to resolve your request. Please call 311 if further information is required. (311 Open Data Activity Detail version).
"geometry_point",
"count", -- Number of service requests - usually 1. To be used for reporting purposes.
"location_city",
"location_state",
":@computed_region_7ccj_gre3",
":@computed_region_da6r_6gkw",
":@computed_region_eq8d_jmrp",
":@computed_region_mnf4_kaez",
":@computed_region_5jki_au6x",
":@computed_region_izdr_ja4x",
":@computed_region_ecxu_fw7u"
FROM
"edmonton-ca/311-explorer-ukww-xkmj:latest"."311_explorer"
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 edmonton-ca/311-explorer-ukww-xkmj with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.edmonton.ca. When you queryedmonton-ca/311-explorer-ukww-xkmj: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.edmonton.ca, 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 \
"edmonton-ca/311-explorer-ukww-xkmj" \
--handler-options '{
"domain": "data.edmonton.ca",
"tables": {
"311_explorer": "ukww-xkmj"
}
}'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, edmonton-ca/311-explorer-ukww-xkmj is just another Postgres schema.