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 commercial_vacancy_multifamily table in this repository, by referencing it like:
"citydata-mesaaz-gov/commercial-vacancy-multifamily-v8b7-pc2z:latest"."commercial_vacancy_multifamily"or in a full query, like:
SELECT
":id", -- Socrata column ID
"mf_unit_vacancy_rate", -- The number of vacant Multi-Family units in Mesa against the total inventory of Multi Family units in Mesa.
"under_construction_percent",
"concessions_percentage", -- The percentage of effective rent per unit over the asking rent per unit.
"calendar_year", -- The year that the data pertains to.
"net_absorption_units", -- The total amount of Multi-Family units in Mesa that was net absorbed, which is the total units occupied less the total units vacated over a period of time.
"effective_rent_per_unit", -- The average price of rent paid per unit over the term by a tenant, adjusted downward from asking for concessions paid for by the landlord (such as free rent, moving expenses, or other allowances)
"total_number_of_mf_units", -- Total number of existing Multi-Family units in Mesa.
"asking_rent_per_unit", -- The asking price of rent per Multi-Family unit in Mesa.
"annual_year_over_year_growth", -- The year-over-year growth in asking rent price over the same quarter from the previous year. i.e. Q3 2013 to Q3 2014.
"effective_rent_per_square", -- The average price of rent paid per square foot over the term by a tenant, adjusted downward from asking for concessions paid for by the landlord (such as free rent, moving expenses, or other allowances)
"number_of_units_delivered", -- The total number of new Multi-Family units that were completed in a given period of time.
"deliveries_percent",
"location", -- Indicates if the row is part of the Downtown area or not
"calendar_year_and_quarter", -- The 3-month period, or quarter, that the data pertains to.
"quarter_date", -- The 3-month period, or quarter, that the data pertains to in date format.
"average_square_footage_of", -- Average square footage of existing Multi-Family units in Mesa.
"number_of_buildings_under", -- The total number of new Multi-Family buildings that are under construction in a given period of time.
"number_of_buildings_delivered", -- The total number of new Multi-Family buildings that were completed in a given period of time.
"annual_year_over_year_growth_1", -- The year-over-year growth in effective rent price over the same quarter from the previous year. i.e. Q3 2013 to Q3 2014.
"asking_rent_per_sf", -- The average asking price of rent per square foot for Multi-Family units in Mesa.
"number_of_vacant_mf_units", -- The total number of vacant Multi-Family units in Mesa.
"vacancy_growth_year", -- The percentage change in the vacancy rate for the quarter compared to the same quarter in the previous year.
"annual_year_over_year_growth_2", -- The year-over-year change in occupancy over the same quarter from the previous year. i.e. Q3 2013 to Q3 2014.
"total_percent_occupied", -- Percentage of the Inventory Square Footage in Mesa that is occupied.
"number_of_units_under", -- The total number of new Multi-Family units that are under construction in a given period of time
"building_inventory", -- Total number of existing Multi-Family buildings in Mesa.
"number_of_occupied_mf_units", -- The number of occupied Multi-Family units in Mesa.
"net_absorption_percent" -- The percent of units absorbed in the current quarter compared to the total number of occupancy units in the same quarter.
FROM
"citydata-mesaaz-gov/commercial-vacancy-multifamily-v8b7-pc2z:latest"."commercial_vacancy_multifamily"
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 citydata-mesaaz-gov/commercial-vacancy-multifamily-v8b7-pc2z with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at citydata.mesaaz.gov. When you querycitydata-mesaaz-gov/commercial-vacancy-multifamily-v8b7-pc2z: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
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 citydata.mesaaz.gov, 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 \
"citydata-mesaaz-gov/commercial-vacancy-multifamily-v8b7-pc2z" \
--handler-options '{
"domain": "citydata.mesaaz.gov",
"tables": {
"commercial_vacancy_multifamily": "v8b7-pc2z"
}
}'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, citydata-mesaaz-gov/commercial-vacancy-multifamily-v8b7-pc2z is just another Postgres schema.