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 wdfwcreel_analysis_interview table in this repository, by referencing it like:
"wa-gov/wdfwcreel-analysis-interview-rpax-ahqm:latest"."wdfwcreel_analysis_interview"or in a full query, like:
SELECT
":id", -- Socrata column ID
"location_type", -- Defines if the location is a discrete site or a broader section
"interview_id", -- Primary key id value for record in interview table
"creel_event_id", -- Primary key id value for record in creel_event table
"fishing_start_time", -- Time the angling group began fishing
"fishery_name", -- Name of fishery being monitored
"section_num", -- Section number assigned to survey location
"comment_txt", -- Comments pertaining to the interview
"target_species", -- Species the angling group was targeting
"interview_time", -- Time the angling group was interviewed
"water_body", -- Waterbody where angling party fished
"location_id", -- Primary key id value for the fishing location if present, otherwise the id value for the interview location
"fishing_location", -- Location where the angling party primarily fished
"pole_count", -- Count of poles used simultaneously by interview party
"location_season_name", -- Optional name for location specific to the fishery
"angler_count", -- Count of people angling in the interview party
"project_name", -- Data collection project name
"event_date", -- Date interview was conducted
"vehicle_count", -- Count of vehicles associated with angling party
"total_group_count", -- Total count of people in the interview party
"boat_type", -- Type of boat used if applicable
"direct_census_bank", -- The assumed spatial expansion of boat anglers in a particular section used when census count data are unavailable
"indirect_census_bank", -- The assumed spatial expansion of bank anglers in a particular section used when census count data are unavailable
"p_census_boat", -- The asssumed proportion of bank anglers in a particular section that are surveyed during a census effort count
"p_census_bank", -- The asssumed proportion of bank anglers in a particular section that are surveyed during a census effort count
"previously_interviewed", -- Flag to indicate if the angling party was previously interviewed that day
"trailer_count", -- Count of trailers associated with angling party
"fish_from_boat", -- Indicator if the party primarily fished out of a boat or watercraft
"boat_used", -- Indicator if the party used a boat or other watercraft
"trip_guided", -- Indicator if the angling trip was guided
"crc_area", -- Catch record card area
"state_residence", -- Primary residence state of angling party
"surveyor_num", -- Survey number assigned to each creel survey location
"survey_type", -- Defines if the location is used as an index or census
"trip_status", -- Defines if the angling trip was complete or still in progress when the party was interviewed
"angler_type", -- Categorical classification of angler to bank or boat used by some projects
"modified_datetime", -- Date record was modified
"created_datetime", -- Date record was created
"zip_code", -- Zip code(s) of angling party members
"fishing_end_time", -- Time the angling group stopped fishing
"interview_location", -- Location where the interview occurred
"interview_number" -- Interview number
FROM
"wa-gov/wdfwcreel-analysis-interview-rpax-ahqm:latest"."wdfwcreel_analysis_interview"
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 wa-gov/wdfwcreel-analysis-interview-rpax-ahqm with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.wa.gov. When you querywa-gov/wdfwcreel-analysis-interview-rpax-ahqm: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.wa.gov, 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 \
"wa-gov/wdfwcreel-analysis-interview-rpax-ahqm" \
--handler-options '{
"domain": "data.wa.gov",
"tables": {
"wdfwcreel_analysis_interview": "rpax-ahqm"
}
}'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, wa-gov/wdfwcreel-analysis-interview-rpax-ahqm is just another Postgres schema.