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
"line_number", -- Line number of the specific expenditure for the corresponding invoice.
"payment_type", -- Type of payment used to pay the vendor (Check, Wire or ACI (P-Cards)).
"seg1", -- The numerical value of the fund utilized to pay the expenditure.
"invoice_status", -- Status of the invoice P = Paid or V = Voided
"source_doc_type", -- P = Purchase Order; C = Contract
"jrnl_entry_per", -- The month in which the expenditure was recorded.
"line_item_amount", -- The total value requested for payment through the invoice.
"commodity_code", -- Standard classification codes (NIGP Codes) for products and services used to detail where money is spent within the City-Parish.
"payment_status", -- Status of payment (Cleared and Not Cleared).
"jrnl_entry_year", -- The year in which the expenditure was recorded.
"seg3", -- The numerical value of the function/purpose of the fund used to pay the expenditure.
"object_desc", -- Description of the expenditure type.
"seg2", -- The numerical value of 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.
"invoice_date", -- The date the invoice was issued to the City-Parish for processing and payment.
"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.
"function", -- The function/purpose of the fund used to pay the expenditure.
"seg4", -- The numerical value of the division (within the department) under which the expenditure is authorized and recorded.
"check_number", -- The numerical value of the check issued to pay the vendor for the expenditure.
"check_date", -- The date the check was issued to the vendor.
"invoice_number", -- The id associated with the vendor's invoice that itemizes justification for payment.
"line_item_desc", -- A description of the specific expenditure for the corresponding invoice.
"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.
"commodity_desc", -- Standard classification for products and services used to detail where money is spent within the City-Parish.
"vendor_name", -- The name of the vendor paid through the corresponding invoice.
"vendor_zip" -- The invoice of the vendor paid through the corresponding invoice.
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.
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/open-checkbook-br-7qhq-wwsg: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/open-checkbook-br-7qhq-wwsgCheckout 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/open-checkbook-br-7qhq-wwsg:latestThis will download all the objects for the latest tag of brla-gov/open-checkbook-br-7qhq-wwsg 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/open-checkbook-br-7qhq-wwsg: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/open-checkbook-br-7qhq-wwsg: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/open-checkbook-br-7qhq-wwsg is just another Postgres schema.