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 calgary_equity_index_matrix table in this repository, by referencing it like:
"calgary-ca/calgary-equity-index-matrix-xeek-u7v8:latest"."calgary_equity_index_matrix"or in a full query, like:
SELECT
":id", -- Socrata column ID
"communities", -- A sample list of the main communities in terms of population size that are found within a CSA
"value_label", -- The Total equity score distinguished by type of data (e.g., percentage)
"value", -- The Total equity score obtained by a CSA
"csa_label", -- The CSA number distinguished by the quadrant associated it
"csa", -- Community Service area
"status", -- The designation of a CSA score relative to the target cut-off range for the indicator variable. Based on the score, the CSAs are designated either as above target, below benchmark or between target and benchmark. The status assigned to a CSA defines the equity concern for the CSA
"domain", -- The themes or categories of data types that is used to measure the Calgary Equity Index. Each domain is made of indicator variables
"quadrant", -- The four boundary parts into which Calgary is divided into. These are the NE North East, SE South East, NE North West, and SW South West
"indicator_label", -- Description of the type of data variable that defines an indicator. For instance, some variables are standardized by population while others are simple counts or proportions
"indicator", -- Variable(s) belonging to a domain that is used to measure the Calgary Equity Index
"data_currency", -- Provides information on the year or date data was procured
"colour", -- The colour assigned to a CSA based on the status or score. Each colour communicates a different equity concern. Green areas are at or above the target cut-off and describes areas with a score that signal the least overall equity concern. The red areas are at or below the benchmark cut-off and describes areas with a score that signals high overall burden of inequities. Finally, yellow areas fall between the green and red areas
"domain_label", -- The themes or categories of data types that is used to measure the Calgary Equity Index. Each domain is made of indicator variables
"multipolygon"
FROM
"calgary-ca/calgary-equity-index-matrix-xeek-u7v8:latest"."calgary_equity_index_matrix"
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 calgary-ca/calgary-equity-index-matrix-xeek-u7v8 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 calgary-ca/calgary-equity-index-matrix-xeek-u7v8: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 calgary-ca/calgary-equity-index-matrix-xeek-u7v8Checkout 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 calgary-ca/calgary-equity-index-matrix-xeek-u7v8:latestThis will download all the objects for the latest tag of calgary-ca/calgary-equity-index-matrix-xeek-u7v8 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 calgary-ca/calgary-equity-index-matrix-xeek-u7v8: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 calgary-ca/calgary-equity-index-matrix-xeek-u7v8: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, calgary-ca/calgary-equity-index-matrix-xeek-u7v8 is just another Postgres schema.