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 state_of_iowa_checkbook table in this repository, by referencing it like:
"mydata-iowa-gov/state-of-iowa-checkbook-cyqb-8ina:latest"."state_of_iowa_checkbook"or in a full query, like:
SELECT
":id", -- Socrata column ID
"invoice_date", -- Date of invoice where available, otherwise same as payment date.
"vendor", -- Name of vendor receiving the payment. Some data will be noted as "RESTRICTED" if removed from data for confidentiality purposes.
"program", -- The organizational unit or program within a department associated with the payment
"appropriation_name", -- The legislative authorization for the payment. Some payments are authorized by Iowa Code and do not require an appropriation.
"fund_name", -- The source of funds used to make the payment
"department", -- Name of department, institution or agency making the payment
"fiscal_year_period", -- Reflects twelve periods with July being period 1 and June being period 12. Hold-over payments are reflected in period 12.
"rec_no", -- This is the journal record number which is a unique ID for the record.
"accounting_period", -- Accounting periods as reflected in the State's accounting system. Reflects hold-over periods for payments made after year end.
"fund_code", -- The code designating the source of funds used to make the payment
"fiscal_year", -- Identifies the fiscal year (July 1 - June 30, numbered for the calendar year it ends) the payment was assigned. The fiscal year includes a hold-over period for payments made after year end for good and services received on or before June 30.
"description", -- A description of the type of expenditure such as travel, supplies, utilities, equipment, etc
"invoice_line", -- Placeholder number
"invoice_id", -- Invoice number provided by the vendor where available. If invoice is not available, same as payment number.
"payment_date", -- Date payment was made to the vendor
"payment_id", -- Unique code for the payment based on a concatenation of the doc code, dept number, doc ID, vendor line number and commodity line number from the accounting system
"vendor_id", -- Lists number assigned to vendor. Data removed for confidentiality purposes will be noted as "RESTRICTED" and the vendor number for state employees have been altered to remove the portion of the vendor number based on their Social Security Number.
"expense_category", -- Expense category assigned to the payment
"appropriation_code", -- The code designating the legislative authorization for the payment. Some payments are authorized by Iowa Code and do not require an appropriation.
"service", -- Service reference functions in the state budget, which represent groups of agencies that make expenditures for similar programs and purposes.
"amount", -- Amount of payment to the vendor
"invoice_distribution_line" -- Placeholder number
FROM
"mydata-iowa-gov/state-of-iowa-checkbook-cyqb-8ina:latest"."state_of_iowa_checkbook"
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 mydata-iowa-gov/state-of-iowa-checkbook-cyqb-8ina 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 mydata-iowa-gov/state-of-iowa-checkbook-cyqb-8ina: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 mydata-iowa-gov/state-of-iowa-checkbook-cyqb-8inaCheckout 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 mydata-iowa-gov/state-of-iowa-checkbook-cyqb-8ina:latestThis will download all the objects for the latest tag of mydata-iowa-gov/state-of-iowa-checkbook-cyqb-8ina 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 mydata-iowa-gov/state-of-iowa-checkbook-cyqb-8ina: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 mydata-iowa-gov/state-of-iowa-checkbook-cyqb-8ina: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, mydata-iowa-gov/state-of-iowa-checkbook-cyqb-8ina is just another Postgres schema.