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 dwr_administrative_structures table in this repository, by referencing it like:
"colorado-gov/dwr-administrative-structures-vz77-kxck:latest"."dwr_administrative_structures"or in a full query, like:
SELECT
":id", -- Socrata column ID
"modified", -- Last date time that this record was modified in the DWR database
"range", -- Legal location - range
"county", -- County where the Structure is located
"por_end", -- Date of last measurement in the well’s period of record
"por_start", -- Date of first measurement in the well’s period of record
"associated_case_numbers", -- Water court case number(s) associated with water right
"stream_mile", -- Distance in miles to the confluence with the next downstream water source (or distance to state line)
"water_source", -- Name of the water source as specified in the court case
"structure_name", -- Name of Structure
"coordsns", -- Distance from North/South section line (feet)
"gnis_id", -- National Hydrographic Dataset stream identifier
"structure_type", -- Type of Structure
"longitude", -- Longitude (decimal degrees)
"latitude", -- Latitude (decimal degrees)
"utm_x", -- The x (Easting) component of the Universal Transverse Mercator system. (Zone 12, NAD83 datum)
"current_in_use_code", -- Current in use code of Structure
"structure_name_akas", -- Alternate names for Structure
"coordsew", -- Distance from East/West section line (feet)
"wd", -- DWR water district
"location_accuracy", -- Accuracy of location coordinates
"wdid", -- DWR Unique Structure identifier
"associated_permits", -- List of all well permits associated with WDID
"section", -- Legal location - section number
"location_zip",
"location_state",
"coordsns_dir", -- Direction of measurement from North/South section line
"utm_y", -- The y (Northing) component of the Universal Transverse Mercator system. (Zone 12, NAD83 datum)
"township", -- Legal location - Township number and direction
"contacts", -- Contacts associated with Structure
"designated_basin", -- Designated basin where Structure is located
"user_association", -- User's association that the Structure is included in
"q10", -- Legal location - 10 acre quarter section
"management_district", -- Thirteen local districts, within the Designated Basins, with additional administrative authority
"coordsew_dir", -- Direction of measurement from East/West section line
"associated_meters", -- List of meters associated with WDID
"pm", -- Principal Meridian
"location_address",
"q40", -- Legal location - 40 acre quarter section
"q160", -- Legal location - 160 acre quarter section
"location", -- Latitude/Longitude where the Structure is located
"div", -- DWR Water Division
"location_city",
":@computed_region_nku6_53ud",
"more_information" -- Hyperlink to more information
FROM
"colorado-gov/dwr-administrative-structures-vz77-kxck:latest"."dwr_administrative_structures"
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 colorado-gov/dwr-administrative-structures-vz77-kxck 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 colorado-gov/dwr-administrative-structures-vz77-kxck: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 colorado-gov/dwr-administrative-structures-vz77-kxckCheckout 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 colorado-gov/dwr-administrative-structures-vz77-kxck:latestThis will download all the objects for the latest tag of colorado-gov/dwr-administrative-structures-vz77-kxck 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 colorado-gov/dwr-administrative-structures-vz77-kxck: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 colorado-gov/dwr-administrative-structures-vz77-kxck: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, colorado-gov/dwr-administrative-structures-vz77-kxck is just another Postgres schema.