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 sandy_dep_master_data table in this repository, by referencing it like:
"nj-gov/sandy-dep-master-data-bqxi-fi4r:latest"."sandy_dep_master_data"or in a full query, like:
SELECT
":id", -- Socrata column ID
"disbursed_date", -- Date on which the funds were disbursed
"disbursed_amount", -- Measureable quantity for which the funds were disbursed
"municipality", -- This is the Municipality name or names that pertain to a particular project detail. This column may contain either one Municipality Name, multiple Municipality Names separated by commas, 'statewide', etc.
"project_name", -- The name of a DEP project related to Superstorm Sandy. For example: BLUE ACRES DEMOLITION PROGRAM
"program_description", -- Short Description of the Sandy Blue Acres Buyout Program, Twilight Lake program or any new program
"federal_agency", -- Federal Agency corresponding to the State Agency. Valid value: FEMA, HUD, USDA.
"vendor", -- Vendor Name. The name of a vendor who is doing work for DEP on Superstorm Sandy-related projects(s). NPO, direct vendors
"project_type", -- The type of project that the funds are being used for (Acquisition, Demolition, etc.)
"project_description", -- A textual description of a DEP project related to Superstorm Sandy. For example: BLUE ACRES DEMOLITION PROGRAM = This project facilitates the acquisition and demolition of flood prone, storm damaged properties under the Sandy Blue Acres Buyout Program.
"county", -- This is the name of a county where a Superstorm Sandy related project was worked on. This column may have a single name of a county, a value of 'Statewide' for projects being worked on at a State level, or it will contain the value 'Multi County' for those projects that cross more than on County. A comma separated list of multiple counties relating to one project detail is in the column.
"funding_source", -- Federal Agency that is the funding source for the state Agency, DEP. Valid value: Sandy Blue Acres Buyout Program, Twilight Lake
"obligated_date", -- The date that the funds were committed to this project
"obligated_amount", -- Funds committed to this project but not yet spent
"as_of_date" -- Agency data is up to date as of this date
FROM
"nj-gov/sandy-dep-master-data-bqxi-fi4r:latest"."sandy_dep_master_data"
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 nj-gov/sandy-dep-master-data-bqxi-fi4r 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 nj-gov/sandy-dep-master-data-bqxi-fi4r: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 nj-gov/sandy-dep-master-data-bqxi-fi4rCheckout 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 nj-gov/sandy-dep-master-data-bqxi-fi4r:latestThis will download all the objects for the latest tag of nj-gov/sandy-dep-master-data-bqxi-fi4r 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 nj-gov/sandy-dep-master-data-bqxi-fi4r: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 nj-gov/sandy-dep-master-data-bqxi-fi4r: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, nj-gov/sandy-dep-master-data-bqxi-fi4r is just another Postgres schema.