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 building_permits table in this repository, by referencing it like:
"citydata-mesaaz-gov/building-permits-2gkz-7z4f:latest"."building_permits"or in a full query, like:
SELECT
":id", -- Socrata column ID
"applicant", -- The name of the person that applied for the permit
":@computed_region_fcpr_wj2n",
"council_district", -- City Council District Associated with Property Address
"street_direction", -- The street direction of the property address where the construction will take place
"street_type", -- The street type of the property address where the construction will take place
"issued_year", -- The year the permit was issued by the City of Mesa.
"number_of_dwellings", -- The number of buildings considered to be dwellings for this project.
"residential_permit", -- 'Y' if this is a permit for a new residential building, or 'N' if otherwise.
"description", -- A brief description of the work to be done, sometimes includes location information
"permit_year", -- The year when the permit was issued by City of Mesa
"use", -- COM = Commercial construction; RES = Residential construction; SVC = Application for Service(s)
"street_number", -- The street number of the property address where the construction will take place
"issued_month", -- The month the permit was issued by the City of Mesa
"finaled_year", -- The year the final inspection was completed.
"latitude", -- The latitude for the construction.
"location", -- Geocoded location for the construction
"parcel_number", -- The primary parcel number associated with this permit This number is assigned by Maricopa County and consists of: Book Number (first three characters); Page Number (next two characters); Parcel Number (last three or four characters)
"rowid", -- Unique Row Identifier
"permit_number", -- The case/permit number used to refer to this application or permit record This number consists of: 1) A three-character prefix (BLD or PMT, which means a building permit); 2) A four or two digit year (the year in which the application was made); 3) A hyphen; 4) A five digit sequential number
"property_address", -- The street address where the construction will take place
"street_name", -- The street name of the property address where the construction will take place
"unit_number", -- The Unit Number of Property Address
"issued_date", -- The date the permit was issued by the City of Mesa, allowing construction to begin
"finaled_date", -- The date the final inspection was completed. There can be NO work done after this date.
"finaled_month", -- The month the final inspection was completed.
"status", -- The current status of the permit, which is one of these: Under Review, Approved, Issued, Finaled (meaning project is completed), Void
"value", -- The dollar value of the work to be done, this is set by the Contractor
"icc_value", -- The dollar value of the work to be done based on valuation rates furnished by the International Code Council (ICC)
"type_of_work", -- A more specific description of the Use
"contractor_name", -- The name of the contractor associated with the permit, if any
"contractor_address", -- The address of the contractor associated with the permit, if any
"cofo_date", -- The date a Change of Occupancy was completed
"total_sq_ft", -- The total square footage for work being accomplished by this permit
"number_of_dwelling_units", -- The number of units or apartments for this project.
"longitude" -- The longitude for the construction.
FROM
"citydata-mesaaz-gov/building-permits-2gkz-7z4f:latest"."building_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 citydata-mesaaz-gov/building-permits-2gkz-7z4f 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 citydata-mesaaz-gov/building-permits-2gkz-7z4f: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 citydata-mesaaz-gov/building-permits-2gkz-7z4fCheckout 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 citydata-mesaaz-gov/building-permits-2gkz-7z4f:latestThis will download all the objects for the latest tag of citydata-mesaaz-gov/building-permits-2gkz-7z4f 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 citydata-mesaaz-gov/building-permits-2gkz-7z4f: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 citydata-mesaaz-gov/building-permits-2gkz-7z4f: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, citydata-mesaaz-gov/building-permits-2gkz-7z4f is just another Postgres schema.