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 open_checkbook_br table in this repository, by referencing it like:
"brla-gov/open-checkbook-br-7qhq-wwsg:latest"."open_checkbook_br"or in a full query, like:
SELECT
":id", -- Socrata column ID
"invoice_status", -- Status of the invoice P = Paid or V = Voided
"seg2", -- The numerical value of the department under which the expenditure is authorized and recorded.
"check_date", -- The date the check was issued to the vendor.
"line_number", -- Line number of the specific expenditure for the corresponding invoice.
"source_doc_type", -- P = Purchase Order; C = Contract
"invoice_date", -- The date the invoice was issued to the City-Parish for processing and payment.
"line_item_desc", -- A description of the specific expenditure for the corresponding invoice.
"commodity_code", -- Standard classification codes (NIGP Codes) for products and services used to detail where money is spent within the City-Parish.
"line_item_amount", -- The total value requested for payment through the invoice.
"function", -- The function/purpose of the fund used to pay the expenditure.
"jrnl_entry_year", -- The year in which the expenditure was recorded.
"commodity_desc", -- Standard classification for products and services used to detail where money is spent within the City-Parish.
"seg3", -- The numerical value of the function/purpose of the fund used to pay the expenditure.
"payment_status", -- Status of payment (Cleared and Not Cleared).
"jrnl_entry_per", -- The month in which the expenditure was recorded.
"source_document", -- The purchase order or contract number of the document used to procure the goods or services.
"source_doc_desc", -- A description of the purchase order or contract.
"object", -- The numerical value of the expenditure type used to track and classify types of expenditures within the City-Parish financial system.
"object_desc", -- Description of the expenditure type.
"vendor_name", -- The name of the vendor paid through the corresponding invoice.
"vendor_zip", -- The invoice of the vendor paid through the corresponding invoice.
"fund", -- The budgetary name of the fund utilized to pay the expenditure.
"department", -- The name of the department under which the expenditure is authorized and recorded.
"seg4", -- The numerical value of the division (within the department) under which the expenditure is authorized and recorded.
"division", -- The name of the division (within the department) under which the expenditure is authorized and recorded.
"payment_type", -- Type of payment used to pay the vendor (Check, Wire or ACI (P-Cards)).
"invoice_number", -- The id associated with the vendor's invoice that itemizes justification for payment.
"check_number", -- The numerical value of the check issued to pay the vendor for the expenditure.
"seg1" -- The numerical value of the fund utilized to pay the expenditure.
FROM
"brla-gov/open-checkbook-br-7qhq-wwsg:latest"."open_checkbook_br"
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/open-checkbook-br-7qhq-wwsg with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.brla.gov. When you querybrla-gov/open-checkbook-br-7qhq-wwsg: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 data.brla.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 \
"brla-gov/open-checkbook-br-7qhq-wwsg" \
--handler-options '{
"domain": "data.brla.gov",
"tables": {
"open_checkbook_br": "7qhq-wwsg"
}
}'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, brla-gov/open-checkbook-br-7qhq-wwsg is just another Postgres schema.