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_transactions_of_local_development table in this repository, by referencing it like:
"ny-gov/real-property-transactions-of-local-development-ajgp-mddq:latest"."real_property_transactions_of_local_development"or in a full query, like:
SELECT
":id", -- Socrata column ID
"lease_period", -- Duration (months) of the lease of the transacted property. This field is blank if it doesn't apply or if the authority didn’t enter any information.
"lease_rate", -- Lease rate ($ per square foot) of the transacted property. This field is blank if it doesn't apply or if the authority didn’t enter any information.
"seller_purchaser_tenant_postal_code", -- Zip code of the Seller's/Purchaser's/Tenant's address
"authority_name", -- Name of the Public Authority
"fiscal_year_end_date", -- Date of Fiscal Year end for the Authority
"property_address2", -- Additional address detail of the real property transacted
"property_city", -- City of the real property transacted
"transaction_type", -- Indicates whether the property transaction was an acquisition, disposition (lease), disposition (lease purchase), disposition (sale), or disposition (other).
"purchase_sale_price", -- Price for which the property was transacted (purchased or sold). This field is blank if it doesn't apply or if the authority didn't enter any information.
"market_rate", -- Market rate ($ per square foot) of the transacted property. This field is blank if it doesn't apply or if the authority didn’t enter any information.
"seller_purchaser_tenant", -- Lease rate ($ per square foot) of the transacted property. This field is blank if it doesn't apply or if the authority didn’t enter any information.
"seller_purchaser_tenant_city", -- City of the Seller's/Purchaser's/Tenant's address
"seller_purchaser_tenant_state", -- State of the Seller's/Purchaser's/Tenant's address
"property_transactions", -- No indicates that the authority reported having no real property transactions during the fiscal year. No other information is provided for the reporting period. A blank indicates that property transactions are reported, and data is reported in the remaining fields.
"property_state", -- State of the real property transacted
"property_address1", -- Address of the real property transacted
"property_postal_code", -- Zip code of the real property transacted
"estimated_fair_market_value", -- Estimated fair market value of the transacted property.
"relation_with_authority", -- Yes/No field to indicate whether the Seller/Purchaser/Tenant has, or had within the last two years, a personal or professional relationship with a Board member or senior management of the authority.
"property_description", -- Description of the real property transacted. Can be either commercial building, industrial facility/plant, mixed use, office building, residential building, or vacant lot/Undeveloped land.
"fair_market_description", -- Indicates how the estimated fair market value of the transacted property was determined. Can be either appraisal, competitive bid, or other.
"transaction_type_other", -- Provides additional information about the transaction type. This field is blank if the authority didn’t enter any information.
"transaction_date" -- Date when the property transaction took place.
FROM
"ny-gov/real-property-transactions-of-local-development-ajgp-mddq:latest"."real_property_transactions_of_local_development"
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 ny-gov/real-property-transactions-of-local-development-ajgp-mddq 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 ny-gov/real-property-transactions-of-local-development-ajgp-mddq: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 ny-gov/real-property-transactions-of-local-development-ajgp-mddqCheckout 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 ny-gov/real-property-transactions-of-local-development-ajgp-mddq:latestThis will download all the objects for the latest tag of ny-gov/real-property-transactions-of-local-development-ajgp-mddq 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 ny-gov/real-property-transactions-of-local-development-ajgp-mddq: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 ny-gov/real-property-transactions-of-local-development-ajgp-mddq: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, ny-gov/real-property-transactions-of-local-development-ajgp-mddq is just another Postgres schema.