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 rate_of_dependent_children_removed_from_their_home table in this repository, by referencing it like:
"pa-gov/rate-of-dependent-children-removed-from-their-home-ekf9-na9n:latest"."rate_of_dependent_children_removed_from_their_home"or in a full query, like:
SELECT
":id", -- Socrata column ID
"number_of_removals_description", -- Specifies if the removals are in kinship care or not.
"total_number_of_children_1", -- Indicates if the estimated number of children is not available.
"total_number_of_children", -- Estimated number of children, 0-18 years of age. This count is the 5-year estimate from the United States Census Bureau’s American Community Survey (ACS).
"latitude_longitude", -- Latitude and longitude coordinates in degrees for a centroid point for geographic area.
"county_code_number", -- Pennsylvania county code provided as a number (1-67 for counties, 0 for Commonwealth).
"time_period_dates", -- Start and end dates of time period.
"year", -- Federal fiscal year for measurement (October 1–September 30).
":@computed_region_nmsq_hqvv",
"geocoded_column", -- Georeferenced column for the latitude and longitude for use in mapping visuals.
"total_number_of_children_2", -- Description provided for the Total Number of Children count column.
"geographic_area", -- Region for measure, either total for Commonwealth or individual county.
"time_period", -- Period for measurement (annual, federal fiscal year, or quarterly, if available).
"age", -- Age of children.
"geographic_name", -- Name of geographic area.
":@computed_region_d3gw_znnf",
":@computed_region_amqz_jbr4",
":@computed_region_r6rf_p9et",
"gender", -- Gender of children.
":@computed_region_rayf_jjgk",
"state_fips_code", -- First 2 digits of the 5-digit Federal Information Processing Standard (FIPS) code that designate the state association. Each state has its own 2-digit number and each county within the state has its own 3-digit number which are combined into a 5-digit number to uniquely identify every US county.
"number_of_removals", -- Count of dependent children removed from home due to parental drug use or count of dependent children in kinship care because of parental drug use. This count is provided by the Office of Children, Youth and Families (OCYF) of the Pennsylvania Department of Human Services (DHS).
"county_fips_code", -- Last 3 digits of the 5-digit Federal Information Processing Standard (FIPS) code that designate the county association. Each state has its own 2-digit number and each county within the state has its own 3-digit number which are combined into a 5-digit number to uniquely identify every US county.
"type_of_rate", -- Description of removal rate.
"removal_rate", -- Rate of dependent children removed from home due to parental drug use per 1,000 children or rate of dependent children in kinship care because of parental drug use per 1,000 children.
"county_code_text", -- Pennsylvania county code provided as text (1-67 for counties sorted alphabetically, 0 for Commonwealth).
"number_of_removals_notes" -- Indicates if the number of removals count has been suppressed to protect confidentiality. Counts less than 11 are not provided.
FROM
"pa-gov/rate-of-dependent-children-removed-from-their-home-ekf9-na9n:latest"."rate_of_dependent_children_removed_from_their_home"
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 pa-gov/rate-of-dependent-children-removed-from-their-home-ekf9-na9n with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.pa.gov. When you querypa-gov/rate-of-dependent-children-removed-from-their-home-ekf9-na9n:latest on the DDN, we "mount" the repository using the socrata mount handler. The mount handler proxies your SQL query to the upstream data source, translating it from SQL to the relevant language (in this case SoQL).
We also cache query responses on the DDN, but we run the DDN on multiple nodes so a CACHE_HIT is only guaranteed for subsequent queries that land on the same node.
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 (like this repository), 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, where the author has pushed Splitgraph Images to the repository, you can "clone" and/or "checkout" the data using sgr cloneand sgr checkout.
Mounting Data
This repository is an external repository. It's not hosted by Splitgraph. It is hosted by data.pa.gov, and Splitgraph indexes it. This means it is not an actual Splitgraph image, so you cannot use sgr clone to get the data. Instead, you can use the socrata adapter with the sgr mount command. Then, if you want, you can import the data and turn it into a Splitgraph image that others can clone.
First, install Splitgraph if you haven't already.
Mount the table with sgr mount
sgr mount socrata \
"pa-gov/rate-of-dependent-children-removed-from-their-home-ekf9-na9n" \
--handler-options '{
"domain": "data.pa.gov",
"tables": {
"rate_of_dependent_children_removed_from_their_home": "ekf9-na9n"
}
}'That's it! Now you can query the data in the mounted table like any other Postgres table.
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, pa-gov/rate-of-dependent-children-removed-from-their-home-ekf9-na9n is just another Postgres schema.