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 horseshoe_crab_spawning_survey table in this repository, by referencing it like:
"delaware-gov/horseshoe-crab-spawning-survey-cqsj-dfgg:latest"."horseshoe_crab_spawning_survey"or in a full query, like:
SELECT
":id", -- Socrata column ID
"de_male_90_ci_lower_limit", -- 90% Confidence Interval - Lower limit of values where there exists a 90% probability of male horseshoe crab spawning activity in Delaware
"de_female_90_ci_upper_limit", -- 90% Confidence Interval - Upper limit of values where there exists a 90% probability of female horseshoe crab spawning activity in Delaware
"nj_female_spawning_activity", -- The mean of the total number of female crabs per total area available for the spawning survey on all NJ surveyed beaches
"de_female_spawning_in_may", -- Proportion of females recorded during May of a given survey year on Delaware beaches
"baywide_spawning_activitylunar_period_2", -- The mean of the total number of female crabs per total area available for the spawning survey on all surveyed beaches. The second moon phase (new or full) in May around which surveying occurs - 2 days before, day of, 2 days after.
"total_beaches_surveyed", -- Number of beaches on which the standardized form of the spawning survey was conducted baywide
"baywide_spawning_activitylunar_period_4", -- The mean of the total number of female crabs per total area available for the spawning survey on all surveyed beaches. The second moon phase (new or full) in June around which surveying occurs - 2 days before, day of, 2 days after (typically the last period of surveying).
"baywide_spawning_activity_lunar_period_1", -- The mean of the total number of female crabs per total area available for the spawning survey on all surveyed beaches. The first moon phase (new or full) in May around which surveying begins - 2 days before, day of, 2 days after.
"year", -- Year of survey
"de_female_90_ci_lower_limit", -- 90% Confidence Interval - Lower limit of values where there exists a 90% probability of female horseshoe crab spawning activity in Delaware
"nj_male_spawning_activity", -- The mean of the total number of male crabs per total area available for the spawning survey on all NJ surveyed beaches
"de_male_90_ci_upper_limit", -- 90% Confidence Interval - Upper limit of values where there exists a 90% probability of female horseshoe crab spawning activity in Delaware
"baywide_spawning_activitylunar_period_3", -- The mean of the total number of female crabs per total area available for the spawning survey on all surveyed beaches. The first moon phase (new or full) in June around which surveying occurs - 2 days before, day of, 2 days after.
"numbermalesperfemale", -- The number of males observed in a given spawning season per female observed during that same season.
"baywide_female_cv", -- Coefficient of variation - Unitless description of the amount of variation relative to the mean Index of Spawning Activity (ISA), expressed as a percentage for females
"baywide_male_90_ci_lower_limit", -- 90% Confidence Interval - Lower limit of values where there exists a 90% probability of male horseshoe crab spawning activity
"baywide_male_90_ci_upper_limit", -- 90% Confidence Interval - Upper limit of values where there exists a 90% probability of male horseshoe crab spawning activity
"baywide_female_90_ci_lower_limit", -- 90% Confidence Interval - Lower limit of values where there exists a 90% probability of female horseshoe crab spawning activity
"baywide_female_sd", -- Standard Deviation - Statistical variation of Index of Spawning Activity (ISA) values for females
"de_beaches_surveyed", -- Number of beaches on which the standardized form of the spawning survey was conducted in Delaware
"de_male_spawning_activity", -- The mean of the total number of male crabs per total area available for the spawning survey on all DE surveyed beaches
"de_female_spawning_activity", -- The mean of the total number of female crabs per total area available for the spawning survey on all DE surveyed beaches
"nj_male_90_ci_lower_limit", -- 90% Confidence Interval - Lower limit of values where there exists a 90% probability of male horseshoe crab spawning activity in New Jersey
"nj_male_90_ci_upper_limit", -- 90% Confidence Interval - Upper limit of values where there exists a 90% probability of male horseshoe crab spawning activity in New Jersey
"nj_female_spawning_in_may", -- Proportion of females recorded during May of a given survey year on New Jersey Beaches
"nj_female_90_ci_lower_limit", -- 90% Confidence Interval - Lower limit of values where there exists a 90% probability of female horseshoe crab spawning activity in New Jersey
"nj_female_90_ci_upper_limit", -- 90% Confidence Interval - Upper limit of values where there exists a 90% probability of female horseshoe crab spawning activity in New Jersey
"nj_beaches_surveyed", -- Number of beaches on which the standardized form of the spawning survey was conducted in New Jersey
"baywide_male_sd", -- Standard Deviation - Statistical variation of Index of Spawning Activity (ISA) values for males
"avg_daily_water_temp_in_may_c", -- Average of daily water temperatures recorded at the National Ocean Service station at Lewes, DE (Station Identification Number 8557380) during the month of May in °Celsius
"baywide_male_spawning_activity", -- The mean of the total number of male crabs per total area available for the spawning survey on all surveyed beaches.
"baywide_female_90_ci_upper_limit", -- 90% Confidence Interval - Upper limit of values where there exists a 90% probability of female horseshoe crab spawning activity
"baywide_female_spawning_activity", -- Index of female horseshoe crab spawning activity - mean number of female crabs per square meter per night for Delaware and New Jersey beaches
"baywide_male_cv" -- Coefficient of variation - Unitless description of the amount of variation relative to the mean Index of Spawning Activity (ISA), expressed as a percentage for males
FROM
"delaware-gov/horseshoe-crab-spawning-survey-cqsj-dfgg:latest"."horseshoe_crab_spawning_survey"
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 delaware-gov/horseshoe-crab-spawning-survey-cqsj-dfgg with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.delaware.gov. When you querydelaware-gov/horseshoe-crab-spawning-survey-cqsj-dfgg: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.delaware.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 \
"delaware-gov/horseshoe-crab-spawning-survey-cqsj-dfgg" \
--handler-options '{
"domain": "data.delaware.gov",
"tables": {
"horseshoe_crab_spawning_survey": "cqsj-dfgg"
}
}'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, delaware-gov/horseshoe-crab-spawning-survey-cqsj-dfgg is just another Postgres schema.