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 educational_program_report_2017_current_education table in this repository, by referencing it like:
"pa-gov/educational-program-report-2017-current-education-izb3-j3ae:latest"."educational_program_report_2017_current_education"or in a full query, like:
SELECT
":id", -- Socrata column ID
"program_name", -- The name of the Major or Program of study.
"school_branch", -- Code for the School Branch supplied by PDE. Usually a 4-digit code commonly called the school code. Could be leading zeroes. The number '0' means the main campus.
"administrative_unit_number", -- Administrative Unit Number (AUN) - A 9-digit number assigned by the Pennsylvania Department of Education (PDE) to uniquely identify entities such as school districts, intermediate units, career and technical centers, charter schools, non-public and private schools, higher education institutions, state juvenile correctional institutions, dioceses, private residential rehabilitation institutions, private driver training schools, and libraries
"awards", -- The type of credentialed award the student received upon successful completion within the program of study.
"classification_instruction_code", -- The Classification of Instructional Programs (CIP) provides a taxonomic scheme that supports the accurate tracking and reporting of fields of study and program completions activity. CIP was originally developed by the U.S. Department of Education's National Center for Education Statistics (NCES) in 1980, with revisions occurring in 1985, 1990, and 2000. For information about these early revisions to the CIP, click here or access specific links to historical versions from the resources page. For information about versions after CIP 2000, click the 'change year' link on this site to see the available versions.
"school_year", -- School Year
"instructiontype" -- The major mode of instruction for this program.
FROM
"pa-gov/educational-program-report-2017-current-education-izb3-j3ae:latest"."educational_program_report_2017_current_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/educational-program-report-2017-current-education-izb3-j3ae 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/educational-program-report-2017-current-education-izb3-j3ae: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/educational-program-report-2017-current-education-izb3-j3aeCheckout 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/educational-program-report-2017-current-education-izb3-j3ae:latestThis will download all the objects for the latest tag of pa-gov/educational-program-report-2017-current-education-izb3-j3ae 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/educational-program-report-2017-current-education-izb3-j3ae: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/educational-program-report-2017-current-education-izb3-j3ae: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/educational-program-report-2017-current-education-izb3-j3ae is just another Postgres schema.