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 sdot_street_use_signin_data table in this repository, by referencing it like:
"performance-seattle-gov/sdot-street-use-signin-data-e7yq-b6br:latest"."sdot_street_use_signin_data"or in a full query, like:
SELECT
":id", -- Socrata column ID
"servicehours", -- Calculated field: Calculates TimeCompletedTime minus TimeReachedTime in hours. Used for calculating service times longer than 2 hours.
"vrl_visit_reason", -- Raw data: Visit reasons updated in July 2013 and February 2014. Prior to February 2014, visitors self-selected. Post February 2014, qualified screeners made the selections. Data unreliable prior to February 2014. Exclude Staff Use Only -- this checks visitors in for screening. After screening, customers are signed back in for the a specific visit reason. Counting both would inflate visit counts. Visitors may check in more than once for other categories since they may need to see multiple reviewer types depending on the complexity of their project(s).
"timereacheddate", -- Raw data: Date customer reached by permit reviewer.
"timeintime", -- Raw data: Time customer signed into system. Start of Wait Time. (Socrata does not recognize this as a time field. Format: h:mm:ss AM/PM)
"timereachedtime", -- Raw data: Time customer reached by permit reviewer. End of Wait time. Start of Service time. (Socrata does not recognize this as a time field. Format: h:mm:ss AM/PM)
"waittime", -- Calculated field: TimeReachedTime minus TimeInTime in minutes.
"meeting", -- Calculated field: Time waiting for meetings does not reflect applicant services team performance. Exclude meetings from calculations.
"week", -- Calculated field: Week number where Monday is day 1 of the week. Some years end up with 53 weeks and some have no year 1.
"visit_id", -- Raw data: Unique ID for visit. Primary Key.
"timeindate", -- Raw data: Date customer signed into system.
"excludeservice", -- Calculated field: Exclude from service time calculations. Calculates TimeCompletedTime minus TimeReachedTime and assumes that if this is greater than 9 hours (the number of hours the counter is open), someone did not click a button and the data is in error. Also returns "Exclude" if the TimeCompletedTime is blank.
"meetwith", -- Raw data: If the service category is "Meeting," this is the Street Use or Urban Forestry employee that the visitor is meeting with.
"greaterthan2hours", -- Calculated field: Was the customer's wait or service time greater than 2 hours?
"excludewait", -- Calculated field: Exclude from wait time calculations. Calculates TimeReachedTime minus TimeInTime and assumes that if this is greater than 9 hours (the number of hours the counter is open), someone did not click a button and the data is in error. Also returns "Exclude" if the TimeReachedTime is blank.
"vrl_visit_reason_id", -- Raw data: Unique ID for Visit reason (category). Foreign key.
"timecompletedtime", -- Raw data: Time customer finished with permit reviewer. End of Service Time. (Socrata does not recognize this as a time field. Format: h:mm:ss AM/PM)
"timecompleteddate", -- Raw data: Date customer finished working with permit reviewer.
"vsl_status", -- Raw data: Status of the customer at the time the data was last uploaded. If the date is more than a day older than the data and the status is not Completed, a button was not clicked. All visitors leave Street Use by 5:00 PM each day.
"servicetime", -- Calculated field: TimeCompletedTime minus TimeReachedTime in minutes.
"waithours" -- Calculated field: Calculates TimeReachedTime minus TimeInTime. Used to calculate wait times greater than two hours.
FROM
"performance-seattle-gov/sdot-street-use-signin-data-e7yq-b6br:latest"."sdot_street_use_signin_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 performance-seattle-gov/sdot-street-use-signin-data-e7yq-b6br 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 performance-seattle-gov/sdot-street-use-signin-data-e7yq-b6br: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 performance-seattle-gov/sdot-street-use-signin-data-e7yq-b6brCheckout 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 performance-seattle-gov/sdot-street-use-signin-data-e7yq-b6br:latestThis will download all the objects for the latest tag of performance-seattle-gov/sdot-street-use-signin-data-e7yq-b6br 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 performance-seattle-gov/sdot-street-use-signin-data-e7yq-b6br: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 performance-seattle-gov/sdot-street-use-signin-data-e7yq-b6br: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, performance-seattle-gov/sdot-street-use-signin-data-e7yq-b6br is just another Postgres schema.