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 wdfwcoded_wire_tag_fish_recoveries table in this repository, by referencing it like:
"wa-gov/wdfwcoded-wire-tag-fish-recoveries-auvb-4rvk:latest"."wdfwcoded_wire_tag_fish_recoveries"or in a full query, like:
SELECT
":id", -- Socrata column ID
"returnyear", -- Assigned year of fish return, based upon the brood class. Usually the same as calendar year, except for coho and steelhead escapement.
"forklength_cm", -- Measured fork length in centimeters
"tagcode", -- Tag code reading from the wire found in the snout
"processproject", -- Agency or sub-agency responsible for coring the fish snout and reading the wire extracted.
"mark", -- Recorded external mark on the fish
"verifieddate", -- Description Date and time of record verification
"projectfishnumber", -- Unique fish identification number used for study
"internalid",
"otolithnumber", -- Fish identification number used for otolith tissue sample
"releasedtagnoadclipcnt", -- Calculated number of tagged fish released without an adipose fin clip mark. Not an imported field from PSC.
"firstreleasedate", -- First date of fish release
"samplecardrecordnumber", -- Card sequential record number with associated sampling information
"lastreleasedate", -- Last date of fish release.
"recoverydate", -- Date on which the fish were checked for wire.
"releasesite", -- Geographic location of the release event
"headnumber", -- Sequential number assigned to snout when snouts are bagged during collection under one label
"rearinghatchery", -- Geographic location of the site where fish were reared
"releaseagency", -- Agency responsible for releasing this group into waters of the state
"psnet_recoverygeartype", -- Commercial gear used in the Puget Sound Net fishery from which snouts were collected if applicable
"fishcomments",
"locationcode", -- Primary area code as indicated on the snout label.
"releasecomments",
"releasedtagadclipcnt", -- Calculated number of tagged fish released with an adipose fin clip mark. Not an imported field from PSC.
"psc_code", -- PSC code for geographic area where fish was recovered
"releaseduntagadclipcnt", -- Calculated number of untagged fish released with an adipose fin clip mark. Not an imported field from PSC.
"locationname", -- Short description of the recovery location
"recoverygeartype", -- Method used to harvest or collect the fish.
"samplecardnumber", -- Card number used in collecting sampling information
"releaseduntagnoadclipcnt", -- Calculated number of untagged fish released without an adipose fin clip mark. Not an imported field from PSC.
"baglabelcomments",
"scalecardlinenumber", -- Line number from the the card containing scales from this fish for aging purposes
"stockname", -- Geographic location name of the fish stock
"scalecardnumber", -- Number of the card containing scales from this fish for aging purposes
"baglabel", -- Identifying number on the label that accompanies one or more snouts from the collection point to the tag recovery lab.
"species", -- Species of the fish, as identified by the person collecting the snout.
"tagresult", -- Results of processing the snout and reading the wire
"run", -- Run timing of the fish.
"maturity", -- Age class assignment of the fish, based upon length or true saltwater age (the latter used by WDFW Snake River Lab).
"sampletype", -- Describes the sampling method and the sampling group that collected the snouts
"broodyear", -- Calendar year when majority of parents spawned (definition from PSC CWT data specifications)
"releaserun", -- Run timing of this release group
"fishertype", -- Type of commercial fisher harvesting fish
"sex" -- Sex of fish
FROM
"wa-gov/wdfwcoded-wire-tag-fish-recoveries-auvb-4rvk:latest"."wdfwcoded_wire_tag_fish_recoveries"
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/wdfwcoded-wire-tag-fish-recoveries-auvb-4rvk 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/wdfwcoded-wire-tag-fish-recoveries-auvb-4rvk: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/wdfwcoded-wire-tag-fish-recoveries-auvb-4rvkCheckout 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/wdfwcoded-wire-tag-fish-recoveries-auvb-4rvk:latestThis will download all the objects for the latest tag of wa-gov/wdfwcoded-wire-tag-fish-recoveries-auvb-4rvk 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/wdfwcoded-wire-tag-fish-recoveries-auvb-4rvk: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/wdfwcoded-wire-tag-fish-recoveries-auvb-4rvk: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/wdfwcoded-wire-tag-fish-recoveries-auvb-4rvk is just another Postgres schema.