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 permits_blds table in this repository, by referencing it like:
"nola-gov/permits-blds-72f9-bi28:latest"."permits_blds"or in a full query, like:
SELECT
":id", -- Socrata column ID
"permitclassmapped", -- Residential or Non-Residential property type
"location_city",
":@computed_region_evki_aju8",
"workclassmapped", -- Whether a property is new or existing
":@computed_region_7fw3_kdpf",
"permittypedesc", -- Specific permit type, full name
"location", -- Latitude and longitude of the permit site, derived from its X-Y coordinates
"workclass", -- Specific permit type, full name - BLDS specifies "raw values indicating whether a property is new or existing". New Orleans does not have values as such, but one permit type is "New Construction"
"permitnum", -- Permit number
"originalzip", -- The zip code of the permit
":@computed_region_m56f_hbma",
"originaladdress1", -- The permit's street address
"contractortrade", -- Trade or trades of contractors associated with the permit
"statuscurrent", -- The most recently completed event in the permit's workflow (e.g. "Application Submitted", "Zoning Review", etc.)
"originalcity", -- Always "New Orleans"
"permitclass", -- Property type (e.g. "Single Family", "Business Use", "Multi-Family")
"contractorcompanyname", -- Name or names of contractors associated with the permit
"contractortrademapped", -- Trade or trades mapped to values standardized by BLDS
":@computed_region_spev_d8jm",
"statusdate", -- The date on which the most recent event was completed (see StatusCurrent)
":@computed_region_sikx_bdeb",
"location_zip",
"publisher", -- Publishing authority - always "City of New Orleans"
"completedate", -- Date when the permit was closed - for any reason (e.g. Certificate of Occupancy or Completion issued, application withdrawn, application denied, etc.)
"issuedate", -- Date permit was issued
"expiresdate", -- Projected expiration date of permit
"permittype", -- Abbreviated permit type (also used as the suffix of each permit number)
"location_state",
"contractorstatelic", -- Always "LA"
"link", -- Link to the permit and it's related public documents and data on onestopapp.nola.gov (based on the permit's reference code)
"estprojectcost", -- Construction value, based on a copy of the construction contract or an itemized estimate in the case of self-performed work
"fee", -- Total permit fees, in dollars
"coissueddate", -- Date of Certificate of Occupancy (if applicable)
"permittypemapped", -- Trade or trades mapped to values standardized by BLDS
":@computed_region_k37d_then",
"applieddate", -- Date that the application was submitted to Safety & Permits
"contractorlicnum", -- City license number of electrical and/or mechanical contractor (state contractor licenses are not included)
":@computed_region_ewbu_t8bu",
"description", -- Detailed description of work permitted
"originalstate", -- Always "LA"
"pin", -- The assessor's tax bill number for the parcel
"totalsqft", -- Square footage of new construction or addition (if applicable)
"location_address",
"statuscurrentmapped", -- StatusCurrent event names mapped to values standardized by BLDS
":@computed_region_u4yh_3wk9"
FROM
"nola-gov/permits-blds-72f9-bi28:latest"."permits_blds"
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 nola-gov/permits-blds-72f9-bi28 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 nola-gov/permits-blds-72f9-bi28: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 nola-gov/permits-blds-72f9-bi28Checkout 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 nola-gov/permits-blds-72f9-bi28:latestThis will download all the objects for the latest tag of nola-gov/permits-blds-72f9-bi28 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 nola-gov/permits-blds-72f9-bi28: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 nola-gov/permits-blds-72f9-bi28: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, nola-gov/permits-blds-72f9-bi28 is just another Postgres schema.