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 violations table in this repository, by referencing it like:
"norfolk-gov/violations-agip-sqwc:latest"."violations"or in a full query, like:
SELECT
":id", -- Socrata column ID
"violation_id", -- A unique identifier assigned to the violation for tracking and reference purposes.
"gpin", -- A specific identifier for the parcel or land associated with the violation within the City's grid system.
"tax_account", -- The tax account number linked to the property or parcel associated with the violation for tax assessment purposes.
"address", -- The physical location or street address to which the violation is assigned.
"latitude", -- The latitude of the parcel.
"longitude", -- The longitude of the parcel.
"ward", -- The Ward that the parcel is within.
"superward", -- The Superward that the parcel is within.
"civic_league", -- If applicable, the Civic League that the parcel is within.
"created_date", -- The date the violation was created in the City of Norfolk’s violation tracking system.
"last_modified_date", -- The date the violation was last modified in the City of Norfolk’s violation tracking system.
"corrected_date", -- The date the violation was corrected.
"abatement_date", -- The date that the violation is required to be corrected or remedied to bring the property to compliance.
"complaint_id", -- A unique identifier assigned to the complaint that is related to the violation. The complaint will precede a violation being issued. If a violation does not have a Complaint ID listed, then it may have occurred when an inspector observed it during an inspection or an additional violation was noted in addition to the original complaint.
"status", -- The status of the violation. Values include “Closed – Corrected”, “Closed – Administrative Decision”, “Closed – NA Contractor Completed”, “New”, “Extension Granted”, “Warning Issued”, “Work in Progress”, “Not Corrected”, and others.
"ordinance", -- A brief description of the ordinance under which the violation was issued. Values may include a numeric code which matches to the Virginia Maintenance Code or the Norfolk Municipal Code. Values include “Tall Weeds and Grass”, “Trash And Debris”, “Inoperable Vehicle”, “Abandoned Vehicle”, “304.2 General Requirements-Exterior Structure”, “504.1 Plumbing Facilities and Fixture Requirements General Plumbing Systems”, “Parking-Unimproved”, “Graffiti”, and others.
"department" -- Lists the department that observed and issued the violation.
FROM
"norfolk-gov/violations-agip-sqwc:latest"."violations"
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 norfolk-gov/violations-agip-sqwc 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 norfolk-gov/violations-agip-sqwc: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 norfolk-gov/violations-agip-sqwcCheckout 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 norfolk-gov/violations-agip-sqwc:latestThis will download all the objects for the latest tag of norfolk-gov/violations-agip-sqwc 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 norfolk-gov/violations-agip-sqwc: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 norfolk-gov/violations-agip-sqwc: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, norfolk-gov/violations-agip-sqwc is just another Postgres schema.