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 tax_increment_financing_tif_annual_report_analysis table in this repository, by referencing it like:
"cityofchicago/tax-increment-financing-tif-annual-report-analysis-qm7s-3ctt:latest"."tax_increment_financing_tif_annual_report_analysis"or in a full query, like:
SELECT
":id", -- Socrata column ID
"land_building_current", -- Revenue from the sale of land/buildings that was used for industrial, residential, commercial or institutional purposes in the report year
"note_current", -- Proceeds from Notes deposited in the report year
"private_current", -- Revenue generated from a private sector entity in given report year
"bond_current", -- Proceeds from municipal and/or alternate revenue bonds deposited in the report year
"transfers_municipal", -- Revenue transferred from other municipal sources in the report year
"total_expenditure", -- Total amount of expenditures in the report year
"property_tax_increment_current", -- Amount of increment property tax revenue generated in a redevelopment area in a given report year
"note_cumulative", -- Note proceeds deposited from creation through the report year
"municipal_cumulative", -- Sum of Revenue from Municipal to date
"interest_current", -- Interest earnings on the Tax Allocation Fund Balance in the report year
"fund_balance", -- The TIF balance at end of report Year
"cash_expenses", -- Total amount of cash expenditures in the report year
"distribution_of_surplus", -- Property tax increment, not required for the payment of debt obligations or anticipated redevelopment project costs, that is returned to the County Collector for distribution to the taxing districts
"revenue_from_private_sources", -- Sum of all private sector revenue to date
"amount_designated_debt_obligations", -- Total amount of funding allocated for debt obligations
"net_income", -- Gross income minus taxes and other deductions in the report year
"bond_cumulative", -- Bond proceeds deposited from creation through the report year
"municipal_current", -- Revenue from property, sales, and other taxes and transfers from federal and state governments in the report year
"amount_of_original_debt_issuance", -- The original amount of debt issued
"interest_cumulative", -- Sum of all interest earnings to date
"tax_allocation_fund_balance", -- The TIF balance at beginning of report year.
"tif_district", -- Redevelopment project area
"report_year", -- Calendar year to which the record applies
"amount_designated_project_costs", -- Total amount of funding allocated for projects costs
"revenue_from_other_sources", -- Revenue from miscellaneous including note process, bond subsidiaries, non-compliance payment
"descriptions_of_project_costs_to_be_paid", -- Type of project to where funds were previously allocated but not yet spent
"property_tax_increment_cumulative", -- Sum of all property tax incremental revenue generated from creation through the end of the report year
"land_building_cumulative", -- Sum of all land/building sales revenue to date
"surplus_deficit", -- TIF balance at end of report year
"description_of_debt_obligations", -- Type of debt owed by municipality in the report year
"tif_number" -- The unique, numeric ID assigned to the TIF district.
FROM
"cityofchicago/tax-increment-financing-tif-annual-report-analysis-qm7s-3ctt:latest"."tax_increment_financing_tif_annual_report_analysis"
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 cityofchicago/tax-increment-financing-tif-annual-report-analysis-qm7s-3ctt with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.cityofchicago.org. When you querycityofchicago/tax-increment-financing-tif-annual-report-analysis-qm7s-3ctt: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.cityofchicago.org, 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 \
"cityofchicago/tax-increment-financing-tif-annual-report-analysis-qm7s-3ctt" \
--handler-options '{
"domain": "data.cityofchicago.org",
"tables": {
"tax_increment_financing_tif_annual_report_analysis": "qm7s-3ctt"
}
}'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, cityofchicago/tax-increment-financing-tif-annual-report-analysis-qm7s-3ctt is just another Postgres schema.