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 title_and_salary_listing table in this repository, by referencing it like:
"ny-gov/title-and-salary-listing-t3vp-5tka:latest"."title_and_salary_listing"or in a full query, like:
SELECT
":id", -- Socrata column ID
"standard_number", -- Shows whether a Classification Standard has been published for a title. The Standard Number is a seven digit number that is the same as the Title Code for a title or the Title Code for the lowest level title in the series. To See the classification standard, go to the Title Plan page and find that title: http://www.cs.ny.gov/tsplan/tsp.html
"federal_occupational_code_description", -- The federal occupational category description for the title. See http://www.cs.ny.gov/cc/focdef.cfm for further descriptions.
"level_description", -- A description for the code that indicates the title type . Codes exist only for certain title types as follows: Temporary Title, Approved ; Appointed Official ; Pending Budget Approval ; Career Ladder ; Elected Official ; Intermittent ; Journeyman, Approved ; Seasonal Title Only ; Trainee, Approved
"title_code", -- NYS Title Code 7 digit code The first two digits of a title code identify the occupational group to which the title belongs.
"negotiating_unit_description", -- Name of the negotiating unit assignment
"jurisdictional_classification", -- The title's jurisdictional classification code.
"negotiating_unit", -- Two digit numeric code identifying the negotiating unit assignment
"jurisdictional_classification_description", -- The title's jurisdictional classification name.
"effective_date", -- Date the position became effective (was established) by Classification and Compensation; July 1, 1998 indicates that the position was established prior to existing systems capturing that information.
"filled_positions", -- Number of positions filled when report was run
"agency_description", -- Agency Name
"agency_code", -- Five digit code that indicates where the position(s) are located. A value of XXXXX means that the positions exist in more than one agency.
"grade", -- Two-character salary grade assigned to the title.
"federal_occupational_code", -- Identifies the federal occupational category code for the title.
"title_name", -- Long name associated with a NYS job title.
"level" -- A characteristic (code) that helps to identify a title under certain common criteria. Codes exist only for certain title types.
FROM
"ny-gov/title-and-salary-listing-t3vp-5tka:latest"."title_and_salary_listing"
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 ny-gov/title-and-salary-listing-t3vp-5tka 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 ny-gov/title-and-salary-listing-t3vp-5tka: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 ny-gov/title-and-salary-listing-t3vp-5tkaCheckout 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 ny-gov/title-and-salary-listing-t3vp-5tka:latestThis will download all the objects for the latest tag of ny-gov/title-and-salary-listing-t3vp-5tka 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 ny-gov/title-and-salary-listing-t3vp-5tka: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 ny-gov/title-and-salary-listing-t3vp-5tka: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, ny-gov/title-and-salary-listing-t3vp-5tka is just another Postgres schema.