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 parking_garage_and_lot_inventory table in this repository, by referencing it like:
"montgomerycountymd-gov/parking-garage-and-lot-inventory-rd7s-ntxu:latest"."parking_garage_and_lot_inventory"or in a full query, like:
SELECT
":id", -- Socrata column ID
"geolocation", -- Socrata generated location field
"data_modified_datetime", -- The last date and time information pertaining to the facility was modified.
"inactive", -- The total number of spaces within the facility that are currently closed and prohibited from use by any user group.
"restricted", -- The total number of spaces within the facility whose use is restricted to specified groups and is not open to the public.
"carpool", -- The total number of spaces within the facility allocated to Carpool users.
"pcs", -- The total number of spaces within the facility allocated to Parking Convenience Sticker (PCS) users.
"fifteen_hour_limit", -- The total number of spaces within the facility whose posted duration is 15 hours.
"twelve_hour_limit", -- The total number of spaces within the facility whose posted duration is 12 hours.
"nine_hour_limit", -- The total number of spaces within the facility whose posted duration is 9 hours.
"four_hour_limit", -- The total number of spaces within the facility whose posted duration is 4 hours.
"three_hour_limit", -- The total number of spaces within the facility whose posted duration is 3 hours.
"two_hour_limit", -- The total number of spaces within the facility whose posted duration is 2 hours.
"one_hour_limit", -- The total number of spaces within the facility whose posted duration is 1 hour.
"thirty_min_limit", -- The total number of spaces within the facility whose posted duration is 30 minutes.
"five_min_spaces", -- The total number of spaces within the facility whose posted duration is 5 minutes.
"centroid_lng", -- Depicts a digital representation of the facility's location expressed in longitudinal degrees.
"centroid_lat", -- Depicts a digital representation of the facility's location expressed in latitudinal degrees.
"otherinformation", -- Miscellaneous information pertaining to the facility.
"motorcycle_area", -- The total number of motorcycles designed to park in the motorcycle area within the facility.
"motorcycle_spaces", -- The total number of individual motorcycle parking spaces within the facility.
"car_spaces", -- The total number of vehicular spaces, excluding ADA and ADA-Van spaces, within the facility.
"bike_spaces", -- The total number of bicycle spaces found on bicycle-specific racks within the facility.
"ada_van_spaces", -- The total number of accessible parking spaces for vans within the facility.
"ada_spaces", -- The total number of accessible parking spaces for cars within the facility. The total number of accessible parking spaces for vans within the facility.
"total_capacity", -- The total number of vehicular, motorcycle and bicycle spaces within the facility.
"facility_name", -- The established name of the facility.
"clearance_height_inch", -- The maximum vertical clearance permitted within the facility.
"clearance_height_feet", -- The maximum vertical clearance permitted within the facility.
"floors", -- The existing number of levels in the facility including the basement, where applicable.
"payment_options", -- The type of payment methods accepted by the facility.
"hours_requiring_payment", -- The days of the week and corresponding time period in which the facility's customers are required to pay the posted fees.
"address_of_facility", -- The facility's street address plus the street name of the secondary entrance, if applicable.
"facilitynumber", -- The unique number assigned to a facility distinguishing it from the other facilities. Each facility's number falls between 0 - 99.
"district", -- The Parking Lot District (PLD) the facility is located in. There are four PLD's.
":@computed_region_d9ke_fpxt",
":@computed_region_6vgr_duib",
":@computed_region_vu5j_pcmz",
":@computed_region_d7bw_bq6x",
":@computed_region_rbt8_3x7n",
":@computed_region_tx5f_5em3",
":@computed_region_kbsp_ykn9",
"url_to_additionalinformation" -- Link to a webpage administered by MCDOT's Division of Parking Management disclosing further details about the facility.
FROM
"montgomerycountymd-gov/parking-garage-and-lot-inventory-rd7s-ntxu:latest"."parking_garage_and_lot_inventory"
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 montgomerycountymd-gov/parking-garage-and-lot-inventory-rd7s-ntxu 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 montgomerycountymd-gov/parking-garage-and-lot-inventory-rd7s-ntxu: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 montgomerycountymd-gov/parking-garage-and-lot-inventory-rd7s-ntxuCheckout 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 montgomerycountymd-gov/parking-garage-and-lot-inventory-rd7s-ntxu:latestThis will download all the objects for the latest tag of montgomerycountymd-gov/parking-garage-and-lot-inventory-rd7s-ntxu 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 montgomerycountymd-gov/parking-garage-and-lot-inventory-rd7s-ntxu: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 montgomerycountymd-gov/parking-garage-and-lot-inventory-rd7s-ntxu: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, montgomerycountymd-gov/parking-garage-and-lot-inventory-rd7s-ntxu is just another Postgres schema.