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.
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 opendata-maryland-gov/department-of-general-services-dgs-performance-mhr8-d5hm: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 opendata-maryland-gov/department-of-general-services-dgs-performance-mhr8-d5hmCheckout 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 opendata-maryland-gov/department-of-general-services-dgs-performance-mhr8-d5hm:latestThis will download all the objects for the latest tag of opendata-maryland-gov/department-of-general-services-dgs-performance-mhr8-d5hm 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 opendata-maryland-gov/department-of-general-services-dgs-performance-mhr8-d5hm: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 opendata-maryland-gov/department-of-general-services-dgs-performance-mhr8-d5hm: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, opendata-maryland-gov/department-of-general-services-dgs-performance-mhr8-d5hm is just another Postgres schema.