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 asotin_county_immunization_data_by_school table in this repository, by referencing it like:
"wa-gov/asotin-county-immunization-data-by-school-jzrz-dku2:latest"."asotin_county_immunization_data_by_school"or in a full query, like:
SELECT
":id", -- Socrata column ID
"grade_levels", -- Grade levels taught in school building
"number_exempt_for_varicella", -- Number of students with varicella
"number_exempt_for_diphtheria", -- Number of students with an examption for diptheria/tetanus
"percent_exempt_for_varicella", -- Percentage of students with an exemption for varicella
"percent_exempt_for_polio", -- Percentage of students with an exemption for polio
"percent_exempt_for_diphtheria", -- Percentage of students with an exemption for diphtheria/tetanus
"percent_with_personal", -- Percentage of students with a personal exemption
"percent_complete_for_all", -- Percentage of students with completed immunizations
"reported_enrollment", -- Number of students enrolled in the school
"reported", -- Indicates whether or not school immunization rates were reported
"school_year", -- School year in which immunizations were reported
"has_kindergarten", -- Indicates whether or not school includes kindergarten
"address", -- Mailing address of school
"number_exempt_for_hepatitisb", -- Number of students withan examption for hepatitis b
"number_exempt_for_polio", -- Number of students with an examption for polio
"number_exempt_for_pertussis", -- Number of students with an examption for pertussis
"number_with_religious", -- Number of students with a religious exemption
"number_with_medical_exemption", -- Number of students with a medical exemption
"number_with_any_exemption", -- Number of students with any exemptions
"percent_exempt_for_hepatitisb", -- Percentage of students with an exemption for hepatitis b
"percent_exempt_for_measles", -- Percentage of students with an exemption for measles/mumps/rubella
"percent_with_medical_exemption", -- Percentage of students with a medical exemption
"percent_with_any_exemption", -- Percentage of students with any exemption
"type_of_school", -- Indicates whether school is public or private
"number_exempt_for_measles", -- Number of students with an examption for measles/mumps/rubella
"number_with_personal_exemption", -- Number of students with a personal exemption
"number_complete_for_all", -- Number of students with all immunizations
"percent_exempt_for_pertussis", -- Percentage of students with an exemption for pertussis
"percent_with_religious_1", -- Percentage of students with religious membership exemption
"percent_with_religious", -- Percentage of students with religious exemption
"esd", -- Educational Service District in which school is located
"school_name", -- Name of school
"school_district", -- School District in which school is located
"has_6thgrade", -- Indicates whether or not school includes sixth grade
"number_with_religious_1", -- Number of students with religious membership exemption
"county", -- County in which school is located
"city" -- City in which school is located
FROM
"wa-gov/asotin-county-immunization-data-by-school-jzrz-dku2:latest"."asotin_county_immunization_data_by_school"
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/asotin-county-immunization-data-by-school-jzrz-dku2 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/asotin-county-immunization-data-by-school-jzrz-dku2: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/asotin-county-immunization-data-by-school-jzrz-dku2" \
--handler-options '{
"domain": "data.wa.gov",
"tables": {
"asotin_county_immunization_data_by_school": "jzrz-dku2"
}
}'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/asotin-county-immunization-data-by-school-jzrz-dku2 is just another Postgres schema.