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 cityparish_employees table in this repository, by referencing it like:
"brla-gov/cityparish-employees-bj3z-jksg:latest"."cityparish_employees"or in a full query, like:
SELECT
":id", -- Socrata column ID
"department_num", -- Numerical code associated with the department for which an employee works (see department name column)
"uniqueid", -- Unique Identifier
"edupay", -- Educational pay for employees receiving State Supplemental Pay, or for Municipal Fire and Police employees
"middle_initial",
"mealallowpay", -- Allowance for EMS employees
"employment_status", -- Employee's status with the City-Parish. A=Active; I=Inactive
"personnel_status", -- See personnel status description column
"englicnspay", -- Post license experience allowance for licensed professional engineers
"prisonpay", -- Employees assigned to work at the Parish Prison
"state2pcnt", -- Statute requiring Fire employees to receive a raise of at least 2% each year after completion of 3 years of continuous service in the Fire Department. Effective for 20 years or until the employee's 23rd year of service.
"annual_pay", -- Annual salary based on paygrade and step, does not include any additional earnings
"hrly_rate",
"scheduled_hours", -- Scheduled hours per pay period
"employment_end_date", -- End of service date, the employee may have retired, resigned or was terminated
"current_hire_date", -- Most current date employee hired (Does not include broken service with the City-Parish)
"payloc_name", -- Corresponds to the division or location where the employee works
"department_name", -- Corresponds to the City-Parish department for which an employee works
"first_name",
"years_service", -- Years of service with City-Parish based on current hire date
"job_code", -- Numerical value associated with an employee's position (job title)
"pay_range", -- The pay range or grade that is tied to an employee's current pay (one range may be applicable to multiple positions)
"payloc_num", -- Numerical code associated with the division or location where an employee works (see pay location description column)
"last_name",
"carallowpay",
"job_title",
"personnel_status_desc",
"pay_step" -- The step at which an employee is paid within their pay range (there are 21 steps for each pay range)
FROM
"brla-gov/cityparish-employees-bj3z-jksg:latest"."cityparish_employees"
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 brla-gov/cityparish-employees-bj3z-jksg 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 brla-gov/cityparish-employees-bj3z-jksg: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 brla-gov/cityparish-employees-bj3z-jksgCheckout 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 brla-gov/cityparish-employees-bj3z-jksg:latestThis will download all the objects for the latest tag of brla-gov/cityparish-employees-bj3z-jksg 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 brla-gov/cityparish-employees-bj3z-jksg: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 brla-gov/cityparish-employees-bj3z-jksg: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, brla-gov/cityparish-employees-bj3z-jksg is just another Postgres schema.