cityofchicago/additional-dwelling-unit-preapproval-applications-xbwc-ntpx
Icon for Socrata external plugin

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 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 additional_dwelling_unit_preapproval_applications table in this repository, by referencing it like:

"cityofchicago/additional-dwelling-unit-preapproval-applications-xbwc-ntpx:latest"."additional_dwelling_unit_preapproval_applications"

or in a full query, like:

SELECT
    ":id", -- Socrata column ID
    "year_built", -- Year when the existing building on the lot (if any) was built
    "latitude", -- The latitude of the property
    "current_dus", -- Number of legally-established dwelling units on lot
    "street_number", -- Number portion of the property address
    "status_updated_date", -- Date when ADU preapplication status was last updated
    "submission_date", -- Date when ADU preapplication was electronically submitted
    "adu_zone", -- The Additional Dwelling Unit-Allowed Area that the property is located in (See Section 17-7-0570 of the Zoning Ordinance)
    "street_name", -- Street name portion of the property address
    "existing_bldg", -- Whether the preapproval is for an existing building on the lot
    "zoning", -- The zoning district of the property
    "new_adus", -- Proposed number of ADUs
    "max_adus", -- Maximum number of ADUs allowed
    "longitude", -- The longitude of the property
    "aff_adus", -- Minimum number of affordable ADUs
    "comm_area", -- The Community Area of the property
    "address", -- Property address
    "id", -- A unique identifier for the record
    "applicant_name", -- Name of ADU preapproval applicant
    "owner_name", -- Name of property owner (if different than  applicant)
    "location", -- The location of the property in a format that allows for mapping and geographic analysis on this data portal.
    "adu_type", -- The type of ADU
    "ward", -- The Ward (City Council district) of the property
    "street_direction", -- Direction portion of the property address
    "status", -- Status of ADU preapplication
    "prev_adus", -- Whether there is a previous ADU application at the address
    "owner_occ", -- Whether the property is owner occupied
    ":@computed_region_43wa_7qmu", -- This column was automatically created in order to record in what polygon from the dataset 'Wards' (43wa-7qmu) the point in column 'location' is located.  This enables the creation of region maps (choropleths) in the visualization canvas and data lens.
    ":@computed_region_bdys_3d7i", -- This column was automatically created in order to record in what polygon from the dataset 'Census Tracts' (bdys-3d7i) the point in column 'location' is located.  This enables the creation of region maps (choropleths) in the visualization canvas and data lens.
    ":@computed_region_6mkv_f3dw", -- This column was automatically created in order to record in what polygon from the dataset 'Zip Codes' (6mkv-f3dw) the point in column 'location' is located.  This enables the creation of region maps (choropleths) in the visualization canvas and data lens.
    ":@computed_region_vrxf_vc4k", -- This column was automatically created in order to record in what polygon from the dataset 'Community Areas' (vrxf-vc4k) the point in column 'location' is located.  This enables the creation of region maps (choropleths) in the visualization canvas and data lens.
    ":@computed_region_rpca_8um6" -- This column was automatically created in order to record in what polygon from the dataset 'Boundaries - ZIP Codes' (rpca-8um6) the point in column 'location' is located.  This enables the creation of region maps (choropleths) in the visualization canvas and data lens.
FROM
    "cityofchicago/additional-dwelling-unit-preapproval-applications-xbwc-ntpx:latest"."additional_dwelling_unit_preapproval_applications"
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 cityofchicago/additional-dwelling-unit-preapproval-applications-xbwc-ntpx with SQL in under 60 seconds.

This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.cityofchicago.org. When you querycityofchicago/additional-dwelling-unit-preapproval-applications-xbwc-ntpx:latest on the DDN, we "mount" the repository using the socrata mount handler. The mount handler proxies your SQL query to the upstream data source, translating it from SQL to the relevant language (in this case SoQL).

We also cache query responses on the DDN, but we run the DDN on multiple nodes so a CACHE_HIT is only guaranteed for subsequent queries that land on the same node.

Query Your Local Engine

Install Splitgraph Locally
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 (like this repository), 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, where the author has pushed Splitgraph Images to the repository, you can "clone" and/or "checkout" the data using sgr cloneand sgr checkout.

Mounting Data

This repository is an external repository. It's not hosted by Splitgraph. It is hosted by data.cityofchicago.org, and Splitgraph indexes it. This means it is not an actual Splitgraph image, so you cannot use sgr clone to get the data. Instead, you can use the socrata adapter with the sgr mount command. Then, if you want, you can import the data and turn it into a Splitgraph image that others can clone.

First, install Splitgraph if you haven't already.

Mount the table with sgr mount

sgr mount socrata \
  "cityofchicago/additional-dwelling-unit-preapproval-applications-xbwc-ntpx" \
  --handler-options '{
    "domain": "data.cityofchicago.org",
    "tables": {
        "additional_dwelling_unit_preapproval_applications": "xbwc-ntpx"
    }
}'

That's it! Now you can query the data in the mounted table like any other Postgres table.

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, cityofchicago/additional-dwelling-unit-preapproval-applications-xbwc-ntpx is just another Postgres schema.