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 wdfwsalmonid_population_indicators_spi_escapement table in this repository, by referencing it like:
"wa-gov/wdfwsalmonid-population-indicators-spi-escapement-fgyz-n3uk:latest"."wdfwsalmonid_population_indicators_spi_escapement"or in a full query, like:
SELECT
":id", -- Socrata column ID
"sub_population_name", -- A local spawning population that is distinct in timing or location, but does not demonstrate sufficient reproductive isolation to be considered its own stock.
"comments",
"abundance_qty", -- Contains a value reported by regional biologists as being the most current data for the associated stock. This value is used to chart current abundance trends and rate stock status for individual salmonid stocks.
"year", -- Beginning year in which the data was collected, compiled, or reported. Example: stocks that run\spawn in 2005 or from 2005-2006 would have Year=2005.
"report_types", -- Abbreviated names of reporting destinations.
"calculation_type", -- Describes if the Abundance Quantity is expanded\modeled from a measured quantity or is a raw count of fish.
"data_type", -- General description of what is being quantified.
"biologist_methodology_desc", -- "Free form" description by the biologists of the data type’s most current methodology. This could include multiple components of the methodology, such as sampling locations and calculations or models applied to the data that was collected.
"last_update",
"production_type", -- Production type describes the method of spawning and rearing that produced the fish being enumerated.
"data_series_num", -- A number from 1..x for each stock to identify each data series.
"population_name", -- A group of fish that return to spawn in a given area at the same time and that are, for the most part, reproductively isolated from other such groups. A stock may include several local spawning populations that do not demonstrate sufficient reproductive isolation from one another.
"species", -- Common name for the species.
"escapement_methodology_desc",
"stock_number", -- 4 digit numeric designation for each individual stock.
"escapement_methodology"
FROM
"wa-gov/wdfwsalmonid-population-indicators-spi-escapement-fgyz-n3uk:latest"."wdfwsalmonid_population_indicators_spi_escapement"
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 wa-gov/wdfwsalmonid-population-indicators-spi-escapement-fgyz-n3uk 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 wa-gov/wdfwsalmonid-population-indicators-spi-escapement-fgyz-n3uk: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 wa-gov/wdfwsalmonid-population-indicators-spi-escapement-fgyz-n3ukCheckout 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 wa-gov/wdfwsalmonid-population-indicators-spi-escapement-fgyz-n3uk:latestThis will download all the objects for the latest tag of wa-gov/wdfwsalmonid-population-indicators-spi-escapement-fgyz-n3uk 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 wa-gov/wdfwsalmonid-population-indicators-spi-escapement-fgyz-n3uk: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 wa-gov/wdfwsalmonid-population-indicators-spi-escapement-fgyz-n3uk: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, wa-gov/wdfwsalmonid-population-indicators-spi-escapement-fgyz-n3uk is just another Postgres schema.