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 ebrp_tax_roll table in this repository, by referencing it like:
"brla-gov/ebrp-tax-roll-myfc-nh6n:latest"."ebrp_tax_roll"or in a full query, like:
SELECT
":id", -- Socrata column ID
"restora_tax_abatements", -- Determination whether the tax parcel has a property tax reduction for the renovation of existing structures from a qualifying historic or economic development district
"fair_market_val", -- The price at which the property would change hands between a willing buyer and a willing seller
"transfer_date", -- Date of last conveyance
"subdivision_name", -- Name of the subdivision in which the tax parcel is located
"unit_type", -- The type of unit on the tax parcel which may include a structure, lot, or acreage
"structure_use", -- Type of use of the structure including commercial, residential or not determined
"parcel_address", -- The physical or situs address of the tax parcel
"lot_no", -- Lot number of the tax parcel
"ward_no", -- Ward number of the tax parcel
"assessment_type", -- The type of assessment used to determine taxes including personal property, real property, or public service. Personal property includes machinery and equipment, fixtures, furniture, and other items that are movable in nature and utilized in a business. Real property includes land and all buildings, structures, improvement to the land, and mobile homes. Public service are government and other tax-exempted properties.
"assessment_status", -- Taxing status of the parcel including actual, adjudicated, exempt or restoration abatement (RS). Actual property is real estate that can be taxed and all tax payments are up to date. Property with unpaid taxes is adjudicated to the Parish of East Baton Rouge in accordance with the laws of the State of Louisiana. Public service type property is exempted from taxation. Restoration abatement property is exempt from any new building renovations, but taxes are still owed for the original value.
"taxpayer_name", -- Name of the taxpayer
"taxpayer_addr_1", -- Mailing address of the taxpayer
"taxpayer_addr_2", -- Mailing subaddress of the taxpayer
"taxpayer_addr_3", -- Mailing city, state and ZIP code of the taxpayer
"homestead_exemption", -- A homeowner is entitled to one homestead exemption which is a maximum of $7,500 of the assessed value
"homestead_exempt_type", -- Determination whether the tax parcel qualifies to receive a homestead exemption
"total_value", -- A percentage of the fair market value determined by the use of the property (commercial or residential)
"taxpayer_val", -- The taxable amount for determining Parish taxes derived from the sum of land/acreage value and any improvement value minus any applicable homestead exemption
"tax_freeze", -- Indicates if a tax freeze is applied to this record
"legal_description", -- Full description of the tax parcel which serves as the legal record
"assessment_no", -- The unique property number assigned to each tax parcel for the tax rolls prior to 2017.
"vacant_lot_yn", -- Tax parcel with no structure attached
"assessment_no_new", -- The unique property number assigned to each tax parcel. Also referred to as the Assessment Number.
"tax_year", -- Indicates the year of the Tax Roll
"conv_instrument_no", -- The conveyance instrument number or deed number associated with the last transaction of the parcel.
"instrument_type", -- The transaction type of the last conveyance
"units", -- Total number of structures attached to the tax parcel
"block_no" -- Block or square number in which the tax parcel is located
FROM
"brla-gov/ebrp-tax-roll-myfc-nh6n:latest"."ebrp_tax_roll"
LIMIT 100;Connecting to the DDN is easy. All you need is an existing SQL client that can connect to Postgres. As long as you have a SQL client ready, you'll be able to query brla-gov/ebrp-tax-roll-myfc-nh6n with SQL in under 60 seconds.
Query Your Local Engine
bash -c "$(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/ebrp-tax-roll-myfc-nh6n: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/ebrp-tax-roll-myfc-nh6nCheckout 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/ebrp-tax-roll-myfc-nh6n:latestThis will download all the objects for the latest tag of brla-gov/ebrp-tax-roll-myfc-nh6n 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/ebrp-tax-roll-myfc-nh6n: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/ebrp-tax-roll-myfc-nh6n: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/ebrp-tax-roll-myfc-nh6n is just another Postgres schema.