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 table in this repository, by referencing it like:
"nola-gov/permits-rcm3-fn58:latest"."permits"or in a full query, like:
SELECT
":id", -- Socrata column ID
"currentstatusdate", -- The date on which the most recent event was completed
"location_1_address",
"division", -- City department/division - always SP(Safety & Permits) for building permit dataset
"opencomments", -- Number of permit review comments that have not been resolved or withdrawn
"bondamount", -- Not used by Safety & Permits
"subdivision", -- City Planning Commission's neighborhood name
"totalinspections", -- Total number of inspections required or performed, both complete and incomplete
"totalfees", -- Total permit fees, in dollars
"m_s", -- Master or sub-permit
"location_1_state",
":@computed_region_ewbu_t8bu",
"applicant", -- Name of the individual or entity who filed the permit application
":@computed_region_k37d_then",
":@computed_region_m56f_hbma",
"constrval", -- Construction value, based on a copy of the construction contract or an itemized estimate in the case of self-performed work
":@computed_region_7fw3_kdpf",
":@computed_region_spev_d8jm",
"historicdistrict", -- Historical District name
":@computed_region_sikx_bdeb",
"issuedate", -- Date permit was issued
":@computed_region_evki_aju8",
"bldgarea", -- Square footage of new construction or addition (if applicable)
"councildist", -- Council District (A, B, C, D, E)
"owner", -- Property owner
"contractors", -- Name or names of contractors associated with the permit
"zoning", -- How the property was zoned at the time of the permit application
":@computed_region_u4yh_3wk9",
"unpaidfees", -- Permit fees that have not been paid yet
"nextstatus", -- The next event in the permit's workflow after the most recently completed event
"description", -- Detailed description of work permitted
"projectname", -- If this permit is associated with a City Planning project, that project's title
"pin", -- The assessor's tax bill number for the parcel
"leadagency", -- Always City of New Orleans
"location_1_zip",
"basementar", -- Not used - area of basement in square feet
"baths", -- Optional - number of bathrooms
"address", -- The permit's street address
"location_1", -- Latitude/Longitude coordinates
"daysopen", -- Number of days from filing the application to closing the permit (whether finaled, voided, withdrawn, or denied)
"landuse", -- Property type (e.g. "Single Family", "Business Use", "Multi-Family")
"beds", -- Optional - number of bedrooms
"numstring", -- Permit number
"daysissued", -- Number of days from issuing the permit to closing the permit (whether finaled, voided, withdrawn, or denied)
"currentstatus", -- The most recently completed event in the permit's workflow (e.g. "Application Submitted", "Zoning Review", etc.)
"heattype", -- Optional - type of heating to be installed
"nextstatusdate", -- The date on which the next incomplete event is projected to be completed
"type", -- Permit type description
"filingdate", -- Date that the application was submitted to Safety & Permits
"code", -- Permit type code
"secondfloo", -- Not used - area of second floor in square feet
"isclosed", -- Whether the permit has been closed
"exitreason", -- If the permit application has been closed, the reason for closing it
"location_1_city",
"landuseshort" -- Property type code
FROM
"nola-gov/permits-rcm3-fn58:latest"."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 nola-gov/permits-rcm3-fn58 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-rcm3-fn58: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-rcm3-fn58Checkout 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-rcm3-fn58:latestThis will download all the objects for the latest tag of nola-gov/permits-rcm3-fn58 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-rcm3-fn58: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-rcm3-fn58: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-rcm3-fn58 is just another Postgres schema.