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 performance_measures table in this repository, by referencing it like:
"norfolk-gov/performance-measures-7jsp-eyjg:latest"."performance_measures"or in a full query, like:
SELECT
":id", -- Socrata column ID
"strategic_objective", -- Broad local government service areas used to better understand how city funds are allocated across each of the functional areas. Each program is mapped to a strategic objective and the program measures are used to track progress in the program as well as the strategic objective area.
"fy_2024_projected", -- The projected measure as of FY 2024. This number will be updated when the actual measure is finalized after FY 2024 is complete. Values 99999 = “Yes” and 99998 = “No”. Percentages are expressed as decimals. For example 50% is 0.5 in the dataset.
"fy_2023", -- The metric value as of FY 2023. The fiscal year runs from July 1, 2022 to June 30, 2023. Values 99999 = “Yes” and 99998 = “No”. Percentages are expressed as decimals. For example 50% is 0.5 in the dataset.
"program_name", -- The City of Norfolk program that the performance measure is related to. A program is set of related activities or tasks intended to produce a desired result for a specific population.
"department", -- The City of Norfolk department that defined and tracks the performance measure.
"demand_level", -- Details whether a program has the resources necessary to meet the established standard for each service. Standards are set by compliance regulations or a well-defined expectation. The program’s ability to meet that standard falls into one of three categories: Does Not Meet Demand, Meets Demand – Maintains, or Meets Demand – Exceeds.
"fy_2022", -- The metric value as of FY 2022. The fiscal year runs from July 1, 2021 to June 30, 2022. Values 99999 = “Yes” and 99998 = “No”. Percentages are expressed as decimals. For example 50% is 0.5 in the dataset.
"fy_2021", -- The metric value as of FY 2021. The fiscal year runs from July 1, 2020 to June 30, 2021. Values 99999 = “Yes” and 99998 = “No”. Percentages are expressed as decimals. For example 50% is 0.5 in the dataset.
"measure_description", -- The description of the measured outcome and impact of a program. It is generally the results of an activity, plan, process, or program.
"fy_2025_proposed", -- The proposed measure for FY 2025. This number represents what the department projects the measure will be for the fiscal year. Values 99999 = “Yes” and 99998 = “No”. Percentages are expressed as decimals. For example 50% is 0.5 in the dataset.
"measure_type", -- Defines if a measure is derived from the resident survey or from the department.
"target" -- The goal for the measure in the given fiscal year. It is the standard that is set for each measure and is rooted in either best practices, historical performance, industry regulations, leadership expectation or backlog. Values 99999 = “Yes” and 99998 = “No”. Percentages are expressed as decimals. For example 50% is 0.5 in the dataset.
FROM
"norfolk-gov/performance-measures-7jsp-eyjg:latest"."performance_measures"
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 norfolk-gov/performance-measures-7jsp-eyjg 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 norfolk-gov/performance-measures-7jsp-eyjg: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 norfolk-gov/performance-measures-7jsp-eyjgCheckout 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 norfolk-gov/performance-measures-7jsp-eyjg:latestThis will download all the objects for the latest tag of norfolk-gov/performance-measures-7jsp-eyjg 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 norfolk-gov/performance-measures-7jsp-eyjg: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 norfolk-gov/performance-measures-7jsp-eyjg: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, norfolk-gov/performance-measures-7jsp-eyjg is just another Postgres schema.