Query the Data Delivery Network

Query the DDN

The 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 and query any version of over 40,000 datasets that are hosted or proxied by Splitgraph.

For example, you can query the article_22_green_building_review_projects table in this repository, by referencing it like:


or in a full query, like:

    ":id", -- Socrata column ID
    "devlog_id", -- Project ID number in the Cambridge Development Log publication, if applicable
    "neighborhood", -- Cambridge neighborhood where project located
    "former_site_name", -- Site name prior to initiation of project.
    "project_name", -- Name by which project is known, if applicable
    "primary_address", -- Primary address of the project.
    "ae_ach", -- LEED points achieved in Awareness & Education
    "ae_all", -- LEED points possible in Awareness & Education
    "ea_ach", -- LEED points achieved in Energy & Atmosphere
    "ea_all", -- LEED points possible in Energy & Atmosphere
    "id_ach", -- LEED points achieved in Innovation & Design Process
    "id_all", -- LEED points possible in Innovation & Design Process
    "ss_ach", -- LEED points achieved in Sustainable Sites
    "rp_all", -- LEED points possible in Regional Priority
    "rp_ach", -- LEED points achieved in Regional Priority
    "rating_system_version", -- Year or iteration (version) of the set of standards established within an authorized rating program for a project or building type.
    "rating_level", -- Rating a project is designed to achieve
    "pts_all", -- Total points that possible based on the rating system
    "pts_ach", -- Total points that the project has been designed to achieve
    "pb", -- Planning Board special permit number, if applcaible
    "mr_all", -- LEED points possible in Materials & Resources
    "location", -- Latitude and longitude of project
    "ll_all", -- LEED points possible in Location & Transportation/Linkages
    "ll_ach", -- LEED points achieved in Location & Transportation/Linkages
    "ip_all", -- LEED points possible in Integrative Process
    "ip_ach", -- LEED points achieved in Integrative Process
    "ieq_all", -- LEED points possible in Indoor Environmental Quality
    "ieq_ach", -- LEED points achieved in Indoor Environmental Quality
    "pro_use", -- Primary use of the project
    "pro_type", -- “New Construction” projects are new buildings.. “Substantial Rehabilitation” projects include major renovation to existing buildings.. 
    "pro_stg", -- “Permitting” projects are under review. “Permitted” projects have received development approvals. “Under Construction” projects have received a Building Permit. “Completed” projects have received a Certificate of Occupancy (CO) or a Temporary CO.
    "year_complete", -- Year final Certificate of Occupancy for the project issued.
    "approval_type", -- Type of development review to which project was subject
    "gfa", -- Gross floor area of a project as reviewed
    "mr_ach", -- LEED points achieved in Materials & Resources
    "we_ach", -- LEED points achieved in Water Efficiency
    "we_all", -- LEED points possible in Water Efficiency
    "residential_units", -- Number of residential units in project, if applicable
    "solar_capacity", -- Indicates potential solar capacity of project in kilowatt hours.
    "solar_ready", -- Indicates if project is ready for installation of solar energy system
    "developer_name", -- Project developer or owner
    "master_project", -- Larger development/master plan incorporating the project, if applicable
    "gb_id", -- ID number for Article 22 project review.  May cover one or more buildings.
    "ss_all", -- LEED points possible in Sustainable Sites
    "certified" -- Certification status of the project
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 cambridgema-gov/article-22-green-building-review-projects-ay64-ymwq with SQL in under 60 seconds.

Query Your Local Engine

Install Splitgraph Locally
bash -c "$(curl -sL"

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 cambridgema-gov/article-22-green-building-review-projects-ay64-ymwq: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 cambridgema-gov/article-22-green-building-review-projects-ay64-ymwq

Checkout 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 cambridgema-gov/article-22-green-building-review-projects-ay64-ymwq:latest

This will download all the objects for the latest tag of cambridgema-gov/article-22-green-building-review-projects-ay64-ymwq 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 cambridgema-gov/article-22-green-building-review-projects-ay64-ymwq: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 cambridgema-gov/article-22-green-building-review-projects-ay64-ymwq:latest

This 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, cambridgema-gov/article-22-green-building-review-projects-ay64-ymwq is just another Postgres schema.

Related Documentation: