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 real_property_tax_rates_levy_year_2014_and_beyond table in this repository, by referencing it like:
"montgomerycountymd-gov/real-property-tax-rates-levy-year-2014-and-beyond-mdtv-drkr:latest"."real_property_tax_rates_levy_year_2014_and_beyond"or in a full query, like:
SELECT
":id", -- Socrata column ID
"ssa_development_district_tax", -- Development District and Special Taxing District Tax is levied to finance certain infrastructure improvements through secured bond issuance. Revenues collected are used exclusively for the applicable district.
"ssa_parking_lot_district_tax", -- Parking Lot District Tax funds parking lot districts improvements. Whether a taxpayer pays one of these special area taxes depends on where the property is located.
"ssa_transit_tax", -- Transit Tax is levied Countywide and funds public transportation services including the Ride On bus system.
"ssa_storm_drainage_tax", -- Storm Drainage Tax funds storm drainage improvements. Whether a taxpayer pays one of these special area taxes depends on where the property is located.
"ssa_noise_abatement_district", -- Name of the Noise Abatement District.
"ssa_development_district", -- Name of the Development District.
"general_county_tax", -- The General County tax is levied on all property in the County and funds, in part, such basic services as police protection, elementary and secondary education, the community college, transportation, health and social services, and libraries.
"state_tax", -- This tax is levied by the State of Maryland for the payment of principal and interest on State bonds.
"municipal_district_tax", -- Municipal District Property Tax is levied by each municipal area and generally funds street and sidewalk maintenance, trash removal, tree care, sanitation, and police protection.
"ssa_noise_abatement_district_tax", -- Noise Abatement Tax funds noise abatement district improvements. Whether a taxpayer pays one of these special area taxes depends on where the property is located.
"ssa_urban_district_tax", -- Urban District Tax funds urban district improvements. Whether a taxpayer pays one of these special area taxes depends on where the property is located.
"total_special_service_area_tax", -- The Special Service Area Tax includes Transit, Fire District, Advanced Land Acquisition, Metropolitan, Regional, Recreation, Storm Drainage, Parking Lot District, Urban District, Noise Abatement District, and Development District taxes.
"total_tax_rate", -- Total tax rate.
"ssa_parking_lot_district", -- Name of the Parking Lot District.
"ssa_fire_district_tax", -- Fire District Tax is levied Countywide and funds fire and rescue services.
"ssa_recreation_tax", -- Recreation tax funds recreation facilities and programs. Whether a taxpayer pays one of these special area taxes depends on where the property is located.
"ssa_mncppc_advanced_land_acquisition_tax", -- Advance Land Acquisition Tax is levied Countywide and funds land acquisitions by the Maryland-National Capital Park and Planning Commission (M-NCPPC).
"municipal_district", -- Name of the Municipal District
"levy_year", -- LEVY YEAR
"ssa_urban_district", -- Name of the Urban District.
"tax_class", -- Tax class category the property address is located within.
"ssa_mncppc_metro_politan_tax", -- Metropolitan Tax funds M-NCPPC local park facilities and parks programs. Whether a taxpayer pays one of these special area taxes depends on where the property is located.
"ssa_mncppc_regional_tax" -- Regional Tax funds M-NCPPC planning and administrative programs. Whether a taxpayer pays one of these special area taxes depends on where the property is located.
FROM
"montgomerycountymd-gov/real-property-tax-rates-levy-year-2014-and-beyond-mdtv-drkr:latest"."real_property_tax_rates_levy_year_2014_and_beyond"
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 montgomerycountymd-gov/real-property-tax-rates-levy-year-2014-and-beyond-mdtv-drkr 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 montgomerycountymd-gov/real-property-tax-rates-levy-year-2014-and-beyond-mdtv-drkr: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 montgomerycountymd-gov/real-property-tax-rates-levy-year-2014-and-beyond-mdtv-drkrCheckout 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 montgomerycountymd-gov/real-property-tax-rates-levy-year-2014-and-beyond-mdtv-drkr:latestThis will download all the objects for the latest tag of montgomerycountymd-gov/real-property-tax-rates-levy-year-2014-and-beyond-mdtv-drkr 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 montgomerycountymd-gov/real-property-tax-rates-levy-year-2014-and-beyond-mdtv-drkr: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 montgomerycountymd-gov/real-property-tax-rates-levy-year-2014-and-beyond-mdtv-drkr: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, montgomerycountymd-gov/real-property-tax-rates-levy-year-2014-and-beyond-mdtv-drkr is just another Postgres schema.