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 library_circulation_statistics table in this repository, by referencing it like:
"norfolk-gov/library-circulation-statistics-e68x-a47n:latest"."library_circulation_statistics"or in a full query, like:
SELECT
":id", -- Socrata column ID
"used_marked_item", -- Library items used inhouse for reference only.
"playaway_audio_books", -- Playaway Audio Books
"circulating_federal_depository_government_documents", -- Available government documents from the federal depository that are available via circulation.
"juvenile_nonfiction_digital_books", -- Digital Books Juvenile Non-Fiction available online only for downloading.
"young_adult_vhs_tapes", -- Young Adult VHS Tapes.
"juvenile_dvds", -- Juvenile DVDs.
"adult_magazines", -- Adult Mass Market Magazines.
"e_devices", -- Video Game Controllers, Meeting Room Borrowed, Laptops only available for in house use at Jordan-Newby and Van Wyck branch locations.
"adult_reference_books", -- Reference Books.
"adult_nonfiction_digital_books", -- Digital Books Adult Non-Fiction available online only for downloading.
"juvenile_trade_paperback_books", -- Juvenile Trade Paperback Books.
"digital_audiobooks", -- Audiobooks available online only for downloading.
"dvds", -- DVDs.
"equipment", -- Realia items available for checkout including Puzzles, Board Games, Electricity Usage Monitors, Etc.
"mobile_hotspot_devices", -- Wi-Fi devices.
"young_adult_cd_books", -- Young Adult Books on CD.
"month", -- The month the items were circulated.
"total", -- Total items that were circulated.
"adult_hardcover_books", -- Adult Hardcover Books.
"adult_mass_market_paperback_books", -- Adult Mass Market Paperback Books.
"adult_trade_paperback_books", -- Adult Trade Paperback Books.
"adult_fiction_digital_books", -- Digital Books Adult Fiction available online only for downloading.
"young_adult_hardcover_books", -- Young Adult Hardcover Books.
"young_adult_trade_paperback_books", -- Young Adult Trade Paperback Books.
"young_adult_fiction_digital_books", -- Digital Books Young Adult Fiction available online only for downloading.
"young_adult_nonfiction_digital_books", -- Digital Books Young Adult Non-Fiction available online only for downloading.
"young_adult_dvds", -- Young Adult DVD.
"juvenile_board_books", -- Juvenile Board Books.
"juvenile_cassette_books", -- Juvenile Books on Cassette.
"juvenile_hardcover_books", -- Juvenile Hardcover Books.
"juvenile_mass_market_paperback_books", -- Juvenile Mass Market Paperback Books.
"juvenile_book_kits", -- Juvenile Books with Additional Materials.
"juvenile_fiction_digital_books", -- Digital Books Juvenile Fiction available online only for downloading.
"cassette_books", -- Books on Cassette.
"mp3_cd_books", -- Digital (MP3) Books on CD available for downloads.
"digital_magazines", -- Digital Magazines available online for downloading.
"rated_r_dvds", -- DVDs that are rated R.
"reference_federal_depository_government_documents", -- Available government documents from the federal depository that are only available for reference.
"hoopla_ebooks", -- Total number of digital checkouts from Hoopla.
"interlibrary_loans", -- Interlibrary Loans.
"music_scores", -- Music Scores.
"music_cds", -- Music CDs.
"vhs_tapes", -- VHS tapes.
"year", -- The year the items were circulated.
"location", -- The library branch location.
"book_club_kits", -- Multiple Copies of a Single Title Available for Book Clubs to Borrow.
"express_books", -- Popular titles that have a limited checkout period.
"high_demand_adult_fiction_books", -- High Demand Adult Fiction Titles that have checkout and extension restrictions.
"young_adult_mass_market_paperback_books", -- Young Adult Mass Market Books.
"juvenile_cd_books", -- Juvenile Books on CD.
"juvenile_high_demand_books", -- Juvenile High Demand Titles.
"juvenile_reference_books", -- Juvenile Reference Books.
"juvenile_music_cds", -- Juvenile Music CDs.
"juvenile_vhs_tapes", -- Juvenile VHS Tapes.
"digital_movies", -- Digital Movies available online for downloading.
"digital_music", -- Digital Music available online for downloading.
"stem_equipment", -- Realia items defined as science, technology, engineering, and mathematic (STEM) items available for checkout, including Telescopes, Microscopes, Gopro Cameras, Ukuleles, Etc.
"other_reference_government_documents", -- Available government documents not in the federal depository that are only available for reference.
"cd_books", -- Books on CD.
"other_circulating_government_documents", -- Available government documents not in the federal depository that are available via circulation.
"young_adult_cassette_books", -- Young Adult Books on Cassette.
"rated_r_vhs_tapes", -- VHS tapes that are rated R.
"young_adult_high_demand_books" -- Young Adult High Demand Books.
FROM
"norfolk-gov/library-circulation-statistics-e68x-a47n:latest"."library_circulation_statistics"
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 norfolk-gov/library-circulation-statistics-e68x-a47n 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 norfolk-gov/library-circulation-statistics-e68x-a47n: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 norfolk-gov/library-circulation-statistics-e68x-a47nCheckout 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 norfolk-gov/library-circulation-statistics-e68x-a47n:latestThis will download all the objects for the latest tag of norfolk-gov/library-circulation-statistics-e68x-a47n 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 norfolk-gov/library-circulation-statistics-e68x-a47n: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 norfolk-gov/library-circulation-statistics-e68x-a47n: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, norfolk-gov/library-circulation-statistics-e68x-a47n is just another Postgres schema.