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 public_school_enrollment_by_local_education table in this repository, by referencing it like:
"pa-gov/public-school-enrollment-by-local-education-3zi8-vwkd:latest"."public_school_enrollment_by_local_education"or in a full query, like:
SELECT
":id", -- Socrata column ID
"_12th_grade", -- 12th Grade Enrollment Count
"school_year", -- The School year that runs from Fall to Spring.
"lea_type", -- LEA Type codes are: COMCTC - Comprehensive CTC CS - Charter School IU - Intermediate Unit OCCCTC - Occupational CTC SD - School District SJCI - State Juvenile Correctional Institution.
"k5_am", -- K5 - The second year of a 2-year kindergarten program or the single year of a traditional 1-year kindergarten program. Students are generally 5 years old at the beginning of the school year. K5A represents a K5 Half Day morning (AM) program and K5P represents a K5 Half Day afternoon (PM) program. K5F is used to indicate a K5 Full Day program.
"_1st_grade", -- 1st Grade Enrollment Count
"_5th_grade", -- 5th Grade Enrollment Count
"_7th_grade", -- 7th Grade Enrollment Count
"_8th_grade", -- 8th Grade Enrollment Count
"_10th_grade", -- 10th Grade Enrollment Count
"administrative_unit_number", -- A unique, 9-digit Administrative Unit Number (AUN) assigned by the Pennsylvania Department of Education.
"local_education_agency_lea", -- The name of the Local Education Agency (LEA) that is responsible for educating students counted in Enrollments.
"county_code", -- Pennsylvania 2-digit County Code
"county", -- County name. Pennsylvania has 67 counties.
"pre_kindergarten_am", -- PRE-KINDERGARTEN (PK) - A program enrolling students who are up to two years younger than the entrance age for the local education agency's kindergarten program. PKA represents a PreK Half Day morning (AM) program and PKP represents a PreK Half Day afternoon (PM) program. PKF is used to indicate a PreK Full Day program.
"pre_kindergarten_pm", -- PRE-KINDERGARTEN (PK) - A program enrolling students who are up to two years younger than the entrance age for the local education agency's kindergarten program. PKA represents a PreK Half Day morning (AM) program and PKP represents a PreK Half Day afternoon (PM) program. PKF is used to indicate a PreK Full Day program.
"pre_kindergarten_full_day", -- PRE-KINDERGARTEN (PK) - A program enrolling students who are up to two years younger than the entrance age for the local education agency's kindergarten program. PKA represents a PreK Half Day morning (AM) program and PKP represents a PreK Half Day afternoon (PM) program. PKF is used to indicate a PreK Full Day program.
"k4_am", -- K4 - The first year of a 2-year kindergarten program. Students are generally 4 years old at the beginning of the school year. K4A represents a K4 Half Day morning (AM) program and K4P represents a K4 Half Day afternoon (PM) program. K4F is used to indicate a K4 Full Day program.
"k4_pm", -- K4 - The first year of a 2-year kindergarten program. Students are generally 4 years old at the beginning of the school year. K4A represents a K4 Half Day morning (AM) program and K4P represents a K4 Half Day afternoon (PM) program. K4F is used to indicate a K4 Full Day program.
"k4_full_day", -- K4 - The first year of a 2-year kindergarten program. Students are generally 4 years old at the beginning of the school year. K4A represents a K4 Half Day morning (AM) program and K4P represents a K4 Half Day afternoon (PM) program. K4F is used to indicate a K4 Full Day program.
"k5_pm", -- K5 - The second year of a 2-year kindergarten program or the single year of a traditional 1-year kindergarten program. Students are generally 5 years old at the beginning of the school year. K5A represents a K5 Half Day morning (AM) program and K5P represents a K5 Half Day afternoon (PM) program. K5F is used to indicate a K5 Full Day program.
"k5_full_day", -- K5 - The second year of a 2-year kindergarten program or the single year of a traditional 1-year kindergarten program. Students are generally 5 years old at the beginning of the school year. K5A represents a K5 Half Day morning (AM) program and K5P represents a K5 Half Day afternoon (PM) program. K5F is used to indicate a K5 Full Day program.
"_2nd_grade", -- 2nd Grade Enrollment Count
"_3rd_grade", -- 3rd Grade Enrollment Count
"_4th_grade", -- 4th Grade Enrollment Count
"_6th_grade", -- 6th Grade Enrollment Count
"_9th_grade", -- 9th Grade Enrollment Count
"_11th_grade", -- 11th Grade Enrollment Count
"total" -- Total Enrollment Count
FROM
"pa-gov/public-school-enrollment-by-local-education-3zi8-vwkd:latest"."public_school_enrollment_by_local_education"
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 pa-gov/public-school-enrollment-by-local-education-3zi8-vwkd 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 pa-gov/public-school-enrollment-by-local-education-3zi8-vwkd: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 pa-gov/public-school-enrollment-by-local-education-3zi8-vwkdCheckout 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 pa-gov/public-school-enrollment-by-local-education-3zi8-vwkd:latestThis will download all the objects for the latest tag of pa-gov/public-school-enrollment-by-local-education-3zi8-vwkd 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 pa-gov/public-school-enrollment-by-local-education-3zi8-vwkd: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 pa-gov/public-school-enrollment-by-local-education-3zi8-vwkd: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, pa-gov/public-school-enrollment-by-local-education-3zi8-vwkd is just another Postgres schema.