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 department_of_general_services_dgs_performance table in this repository, by referencing it like:
"opendata-maryland-gov/department-of-general-services-dgs-performance-mhr8-d5hm:latest"."department_of_general_services_dgs_performance"or in a full query, like:
SELECT
":id", -- Socrata column ID
"goal_4g",
"_4g_percent_of_new_construction_architectural_and_engineering_p", -- Description: Tracking the spending for design and construction of State Facilities projects. DGS ensures that projects are budgeted & managed appropriately in order to reach the goal of keeping 100% of projects at or under budget. Footnotes: Under Budget is a project that does not exceed authorized funding and does not access the Statewide Construction Contingency Fund. Projects tracked do not include Dept Of Transportation, University System of Maryland or Dept. Public Safety & Correctional Services
"goal_4fii",
"_4fi_percent_of_new_non_a_e_on_time_procurements_utilizing_the_", -- Description: Tracking the timeliness of the procurement process for goods and services DGS monitors efficiencies in the state procurement process to ensure products and services are delivered on time. Footnote: On-time for Competitive Sealed Bid (CSB) is defined as 90 days
"goal_4e",
"_4e_percent_of_new_architectural_and_engineering_procurement_on", -- Description: Tracking the timeliness of purchasing services for the design of construction projects in State Facilities. The faster the design services are purchased, the quicker the projects can be constructed and occupied. Footnotes: Time Period is from advertisement on eMM until contract award. Under current regulations this 'on-time' is defined as 6 months
"goal_3c", -- The number of LEED certified buildings is a cumulative number of projects developed by the State. As a requirement of State Finance and Procurement Article 3-602.1, the development of LEED Buildings are identified through requirements stated in the previously mentioned statute. Availability of funds ultimately determines whether a project will be built during the Fiscal Year.
"_3c_number_of_state_leed_certified_buildings_2", -- LEED-certified buildings are resource efficient by using less water and energy; reducing greenhouse gas emissions. This increases the life-cycle of State buildings and reduces costs. Footnote: Leadership in Energy and Environmental Design (LEED) Certified
"date",
"goal_4j", -- Description: Green Purchasing Contracts ensure that the State is purchasing sustainable and healthy products. This improves the States environmental impact and provides a better quality of life for Marylanders.
"_4j_percent_of_total_contracts_awarded_as_statewide_green_purch",
"goal_4i",
"_4i_number_of_emergency_contracts_9", -- Description: Contracts that are necessary to avoid or mitigate serious damage to public health, safety and welfare. Footnotes: 9 Projects that are declared an emergency by the Secretary of DGS and reported to BPW. Goal is less than 15 contracts
"goal_4fi",
"goal_3b",
"_3b_energy_consumption_by_all_state_government_facilities_mmbtu", -- Description: Tracking energy consumption for State Buildings encourages transparency and accountability for States Agencies. It is important for Maryland to identify energy savings opportunities and reduce waste. Footnote: MMBTU - One Million British Thermal Units
"goal_3a",
"_3a_number_of_energy_performance_contracts_approved_by_the_boar", -- Description: Energy Performance Contracts are implemented to significantly reduce energy consumption in Maryland State Buildings. Energy Performance contracts maximize energy savings for the State.
"fiscal_year",
"_4fii_percent_of_new_non_a_e_on_time_procurements_utilizing_the" -- Description: Tracking the timeliness of the procurement process for goods and services DGS monitors efficiencies in the state procurement process to ensure products and services are delivered on time. Footnote: On-time for Competitive Sealed Proposal (CSP) is defined as 180 days
FROM
"opendata-maryland-gov/department-of-general-services-dgs-performance-mhr8-d5hm:latest"."department_of_general_services_dgs_performance"
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 opendata-maryland-gov/department-of-general-services-dgs-performance-mhr8-d5hm with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at opendata.maryland.gov. When you queryopendata-maryland-gov/department-of-general-services-dgs-performance-mhr8-d5hm: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 opendata.maryland.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 \
"opendata-maryland-gov/department-of-general-services-dgs-performance-mhr8-d5hm" \
--handler-options '{
"domain": "opendata.maryland.gov",
"tables": {
"department_of_general_services_dgs_performance": "mhr8-d5hm"
}
}'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, opendata-maryland-gov/department-of-general-services-dgs-performance-mhr8-d5hm is just another Postgres schema.