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 issued_signbanner_permits table in this repository, by referencing it like:
"datahub-austintexas-gov/issued-signbanner-permits-8wgz-z8nv:latest"."issued_signbanner_permits"or in a full query, like:
SELECT
":id", -- Socrata column ID
"applicant_name", -- The applicant associated with this permit
"total_sign_face_area", -- The total sign's area on its face
"permit_parent_id", -- This number represents associated projects with the permit's application within the AMANDA database.
"permit_in_date", -- When the permit for the sign was first applied.
"fiscal_year", -- The fiscal year (starting Oct 1) this permit was applied for.
"longitude", -- Longitude of associated property
"sign_in_etj", -- Is this sign within the Austin ETJ?
"permit_final_date", -- Sometimes used to describe the end date for when the permit is no longer applicable.
"applicant_organization", -- An organization associated with this permit (note: not always tied to applicant)
"banner_direction", -- If this is a banner, which direction is it facing.
"permit_work_type", -- Describes more details about the type of sign or banner: lamp post, wall, awning, projection, etc.
"permit_condition", -- Added conditions applied to the permit, such as restrictions.
"calendar_year", -- The calendar year this permit was applied for.
"council_district", -- Council District of associated property
"zip_code", -- Zip code of associated property
"city", -- City of associated property
"permit_number", -- Number of permit (including type)
"illumination_type", -- Does it have external or interal illumination characteristics?
"permit_status", -- Status of the current permit.
"geocoded_column",
"sign_variance_req", -- Was a sign variance required to gain this permit?
"state", -- State of associated property
"permit_sub_type", -- Describes if this is this a sign or banner.
"latitude", -- Latitude of associated property
"banner_location", -- If this is a banner, what is the street address of where it will hang.
"removal_date", -- When is the sign/banner set to be removed.
"permit_expire_date", -- When the permit is no longer applicable.
"permit_description", -- Description of the sign/banner.
"permit_location_name", -- If available, the address or general location of where the permit applies.
"permit_id", -- ID associated with the permit application within the AMANDA database.
"installation_date", -- When is the sign/banner set to be installed.
"engineering_req", -- Will this require engineering efforts?
"submitted_501c3", -- Was a 501c3 Form submitted with this permit?
":@computed_region_rxpj_nzrk",
":@computed_region_m2th_e4b7",
":@computed_region_e9j2_6w3z",
":@computed_region_q9nd_rr82",
":@computed_region_jcrc_4uuy",
":@computed_region_8spj_utxs"
FROM
"datahub-austintexas-gov/issued-signbanner-permits-8wgz-z8nv:latest"."issued_signbanner_permits"
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 datahub-austintexas-gov/issued-signbanner-permits-8wgz-z8nv 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 datahub-austintexas-gov/issued-signbanner-permits-8wgz-z8nv: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 datahub-austintexas-gov/issued-signbanner-permits-8wgz-z8nvCheckout 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 datahub-austintexas-gov/issued-signbanner-permits-8wgz-z8nv:latestThis will download all the objects for the latest tag of datahub-austintexas-gov/issued-signbanner-permits-8wgz-z8nv 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 datahub-austintexas-gov/issued-signbanner-permits-8wgz-z8nv: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 datahub-austintexas-gov/issued-signbanner-permits-8wgz-z8nv: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, datahub-austintexas-gov/issued-signbanner-permits-8wgz-z8nv is just another Postgres schema.