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 taxable_property_values_in_iowa_by_tax_district table in this repository, by referencing it like:
"mydata-iowa-gov/taxable-property-values-in-iowa-by-tax-district-ig9g-pba5:latest"."taxable_property_values_in_iowa_by_tax_district"or in a full query, like:
SELECT
":id", -- Socrata column ID
"prim_long_dec", -- Primary longitude in decimal degrees for the city or township the tax district is located in as provided by U.S. Geological Survey, 19810501, U.S. Geographic Names Information System (GNIS): U.S. Geological Survey, Reston, VA.
"prim_lat_dec", -- Primary latitude in decimal degrees for the city or township the tax district is located in as provided by U.S. Geological Survey, 19810501, U.S. Geographic Names Information System (GNIS): U.S. Geological Survey, Reston, VA.
"military_exempt", -- Amount of taxable property valuations reduced due to military exemptions
"rail", -- Taxable value of property classified as railroad property
"industrial", -- Taxable value of property classified as industrial
"school_district_name", -- Name of school district which the tax district is located
"county_fip", -- A five-digit Federal Information Processing Series code to ensure uniform identification of counties
"district_name", -- Name provided for the tax district
"tax_district_code", -- Unique ID for the tax district
"city_fip", -- A seven-digit Federal Information Processing Series code to ensure uniform identification of cities and other populated places
"other", -- Taxable valuations of property subject to taxation that does not fit under another classification, may include mineral rights, certain bridges and toll bridges
"gas_electric", -- Taxable value of gas and electric utilities as certified by Department of Revenue
"net_w_o_g_e", -- Gross less the military exemption
"gross_w_o_g_e", -- Sum of taxable property values within tax district, excluding gas & electric
"utilities_w_o_g_e", -- Taxable value of all utilities subject to local property tax, excluding gas and electric utilities
"non_reimb_ind_m_e_computers", -- Any taxable machinery and equipment valuation with Community College Jobs Training TIF
"commercial", -- Taxable value of property classified as commercial
"ag_land", -- Taxable value of property classified as agricultural land
"residential", -- Taxable value of property classified as residential
"co_subdivision_fip", -- A ten-digit Federal Information Processing Series code to ensure uniform identification of county subdivisions
"county_name", -- Name of the county the tax district is located
"reimb_ind_m_e_computers", -- Taxable value of property classified as machinery and equipment that was exempted and phased out
"tax_district_location", -- Primary location for the tax district based on Lat/Long for the city or township the tax district is located.
"tday_id", -- Row ID concatenated Assessment Year and Tax District Code
"township_name", -- Name of the township which the tax district is located
"assessment_year", -- Year property values were reported.
"city_name", -- Name of the city the tax district is located
"open_spaces", -- Taxable value of property classified as open space
"ag_building", -- Taxable value of buildings used for agricultural purposes
"property_type", -- Rural, Urban or TIF designation
":@computed_region_3r5t_5243",
":@computed_region_wnea_7qqw",
":@computed_region_i9mz_6gmt",
":@computed_region_e7ym_nrbf",
":@computed_region_uhgg_e8y2"
FROM
"mydata-iowa-gov/taxable-property-values-in-iowa-by-tax-district-ig9g-pba5:latest"."taxable_property_values_in_iowa_by_tax_district"
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/taxable-property-values-in-iowa-by-tax-district-ig9g-pba5 with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at mydata.iowa.gov. When you querymydata-iowa-gov/taxable-property-values-in-iowa-by-tax-district-ig9g-pba5: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 mydata.iowa.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 \
"mydata-iowa-gov/taxable-property-values-in-iowa-by-tax-district-ig9g-pba5" \
--handler-options '{
"domain": "mydata.iowa.gov",
"tables": {
"taxable_property_values_in_iowa_by_tax_district": "ig9g-pba5"
}
}'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, mydata-iowa-gov/taxable-property-values-in-iowa-by-tax-district-ig9g-pba5 is just another Postgres schema.