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 affordable_housing_inventory table in this repository, by referencing it like:
"datahub-austintexas-gov/affordable-housing-inventory-ifzc-3xz8:latest"."affordable_housing_inventory"or in a full query, like:
SELECT
":id", -- Socrata column ID
"private_activity_bonds", -- Indicates use of Private Activity Bonds
"hda", -- Indicates participation in the City of Austin's Housing Development Assistance (HDA) program, either Rental or Ownership
"smart", -- Indicates participation in the City of Austin's SMART program
"contract_id", -- ID for contract associated with the project.
"project_id", -- Unique ID for the project. Primary key.
"project_name", -- Project Name
"ownership", -- Project Owner
"developer", -- Project Developer
"address", -- Project Address
"zip", -- Project Zip Code
"parcel_id", -- Parcel ID according to the Travis Central Appraisal District
"council_district", -- Council District where the project is located.
"unit_type", -- Type of housing: [Single Family, Multifamily, Duplex, Fourplex, ADU]
"housing_tenure", -- Type of Ownership: [Mixed, Non-residential, Ownerships, Rental]
"development_status", -- Phase of life of the project: [Application Received, Certified/Loan Executed, Under Construction, Project Completed, Affordability Period Expired]
"total_units", -- Total number of units for the project
"affordable_units", -- Total number of affordable units for the project
"total_ada_units", -- Total number of ADA units for the project
"psh_units", -- Total number of Permenant Supportive Housing units for the project
"mfi_20", -- Number of units at the project which are income-restricted at or below 20% of the median family income.
"mfi_30", -- Number of units at the project which are income-restricted at or below 30% of the median family income. Not cumulative with lower thresholds.
"mfi_40", -- Number of units at the project which are income-restricted at or below 40% of the median family income. Not cumulative with lower thresholds.
"mfi_50", -- Number of units at the project which are income-restricted at or below 50% of the median family income. Not cumulative with lower thresholds.
"mfi_60", -- Number of units at the project which are income-restricted at or below 60% of the median family income. Not cumulative with lower thresholds.
"mfi_65", -- Number of units at the project which are income-restricted at or below 65% of the median family income. Not cumulative with lower thresholds.
"mfi_70", -- Number of units at the project which are income-restricted at or below 70% of the median family income. Not cumulative with lower thresholds.
"mfi_80", -- Number of units at the project which are income-restricted at or below 80% of the median family income. Not cumulative with lower thresholds.
"mfi_100", -- Number of units at the project which are income-restricted at or below 100% of the median family income. Not cumulative with lower thresholds.
"mfi_120", -- Number of units at the project which are income-restricted at or below 120% of the median family income. Not cumulative with lower thresholds.
"affordability_start_date", -- Date when the project's affordability period begins.
"affordability_expiration_date", -- Date when the project's affordability period expires.
"affordability_period", -- Number of years project will be affordable
"fil_status", -- Status of the fee-in-lieu payment
"cal_fil", -- Calculated payment for the fee-in-lieu
"date_fil_recorded", -- Date when fee-in-lieu payment was received.
"affordability_unlocked", -- Indicates participation in the City of Austin's Affordability Unlocked incentive program.
"dev_agreement", -- Type of development agreement
"density_bonus", -- Type of density bonus
"fil", -- Indicates participation in a City of Austin's fee-in-lieu option.
"lihtc", -- Indicates participation in the Texas Department of Housing and Community Affairs' Low-Income Housing Tax Credit (LIHTC) award
"go_bonds_2006", -- Amount of funds received through the City of Austin's 2006 General Obligation Bonds
"go_bonds_2013", -- Amount of funds received through the City of Austin's 2013 General Obligation Bonds
"go_bonds_2018", -- Amount of funds received through the City of Austin's 2018 General Obligation Bonds
"go_bonds_2022", -- Amount of funds received through the City of Austin's 2022 General Obligation Bonds
"cdbg", -- Amount of funds received through the United States Department of Housing and Urban Development Community Development Block Grant (CDBG)
"cip_funds", -- Amount of funds received through the City of Austin's Capital Improvement Program (CIP)
"home", -- Amount of funds received through the United States Department of Housing and Urban Development HOME Investment Partnerships Program
"htf", -- Amount of funds received through the City of Austin's Housing Trust Fund (HTF)
"project_connect", -- Amount of funds received through Project Connect
"city_subsidy", -- Total amount of funds received through various programs administered by the City of Austin, including those funded by the State of Texas or United States Federal Government.
"ahfc_partnership",
"longitude", -- Longitude of the project.
"latitude" -- Latitude of the project.
FROM
"datahub-austintexas-gov/affordable-housing-inventory-ifzc-3xz8:latest"."affordable_housing_inventory"
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 datahub-austintexas-gov/affordable-housing-inventory-ifzc-3xz8 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 datahub-austintexas-gov/affordable-housing-inventory-ifzc-3xz8: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 datahub-austintexas-gov/affordable-housing-inventory-ifzc-3xz8Checkout 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 datahub-austintexas-gov/affordable-housing-inventory-ifzc-3xz8:latestThis will download all the objects for the latest tag of datahub-austintexas-gov/affordable-housing-inventory-ifzc-3xz8 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 datahub-austintexas-gov/affordable-housing-inventory-ifzc-3xz8: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 datahub-austintexas-gov/affordable-housing-inventory-ifzc-3xz8: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, datahub-austintexas-gov/affordable-housing-inventory-ifzc-3xz8 is just another Postgres schema.