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 american_community_survey_2018_22_estimates_by table in this repository, by referencing it like:
"cambridgema-gov/american-community-survey-2018-22-estimates-by-m9gy-vc6p:latest"."american_community_survey_2018_22_estimates_by"or in a full query, like:
SELECT
":id", -- Socrata column ID
"poverty_rate_single_mother", -- The proportion of single mother families whose income falls below the poverty standard. Only household members are evaluated for poverty status; residents of dormitories and other group quarters arrangements such as nursing homes are not evaluated for poverty status.
"associates_degree_or_some", -- Proportion of population age 25 or older whose highest level of education is either an associates degree or who attended college but have not graduated.
"bachelors_degree", -- Proportion of population age 25 or older whose highest level of education is a Bachelor's degree.
"individual_poverty_rate", -- The proportion of people residing in households whose income falls below the poverty standard. Only household members are evaluated for poverty status; residents of dormitories and other group quarters arrangements such as nursing homes are not evaluated for poverty status.
"centerpoint_y",
":@computed_region_guic_hr4a",
":@computed_region_v7jj_366k",
":@computed_region_rffn_qbt6",
":@computed_region_swkg_bavi",
":@computed_region_e4yd_rwk4",
"_2_household_vehicles", -- The “vehicles available” fields refer to the number of motor vehicles available for use by all members of a household.
"language_asian_pac_is", -- Proportion of persons 5 and older who speak an Asian or Pacific Islander language at home.
"no_hs_diploma_ged", -- Proportion of population age 25 or older without a high school diploma or GED certificate.
"language_indoeuropean", -- Proportion of persons 5 and older who speak an Indoeuropean language other than English or Spanish at home.
"per_capita_income", -- The average amount money income received over the past 12 months for every resident in a geographic area, regardless of age or housing status.
"_3_or_more_vehicles_available", -- The “vehicles available” fields refer to the number of motor vehicles available for use by all members of a household.
"_1_household_vehicle_available", -- The “vehicles available” fields refer to the number of motor vehicles available for use by all members of a household.
"no_vehicles_available", -- The “vehicles available” fields refer to the number of motor vehicles available for use by all members of a household.
"resident_commute_work_at", -- Proportion of Cambridge residents who worked at home.
"resident_commute_other", -- Proportion of Cambridge residents who used a means not included in any other category to commute to work, regardless of the location of place of work. Examples include motorcycle and taxi.
"resident_commute_bike", -- Proportion of Cambridge residents who bicycled to work, regardless of the location of place of work.
"resident_commute_carpool", -- Proportion of Cambridge residents who took a carpool to work, regardless of the location of place of work.
"resident_commute_drive_alone", -- Proportion of Cambridge residents who drove alone to work, regardless of the location of place of work.
"graduate_degree", -- Proportion of population age 25 or older whose highest level of education is graduate degree, including Master's, Doctoral and Professional degrees.
"bachelors_or_graduate_degrees", -- Proportion of population age 25 or older whose highest level of education is a Bachelor's degree or Graduate degree, including Masters, Doctoral and Professional degrees.
"high_school_ged", -- Proportion of population age 25 or older whose highest level of education is a high school diploma or GED certificate.
"neighborhood_name",
"language_other_mixed", -- Proportion of persons 5 and older who speak a language at home other than English and which is not included elsewhere.
"neighborhood_number",
"total_population",
"language_english", -- Proportion of persons 5 and older who speak English at home.
"geocoded_column",
"centerpoint_x",
"poverty_rate_families", -- The proportion of family households whose income falls below the poverty standard. Only household members are evaluated for poverty status; residents of dormitories and other group quarters arrangements such as nursing homes are not evaluated for poverty status.
"resident_commute_walk", -- Proportion of Cambridge residents who walked to work, regardless of the location of place of work.
"resident_commute_public", -- Proportion of Cambridge residents who took public transit to work, regardless of the location of place of work.
"language_spanish" -- Proportion of persons 5 and older who speak Spanish at home.
FROM
"cambridgema-gov/american-community-survey-2018-22-estimates-by-m9gy-vc6p:latest"."american_community_survey_2018_22_estimates_by"
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 cambridgema-gov/american-community-survey-2018-22-estimates-by-m9gy-vc6p 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 cambridgema-gov/american-community-survey-2018-22-estimates-by-m9gy-vc6p: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 cambridgema-gov/american-community-survey-2018-22-estimates-by-m9gy-vc6pCheckout 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 cambridgema-gov/american-community-survey-2018-22-estimates-by-m9gy-vc6p:latestThis will download all the objects for the latest tag of cambridgema-gov/american-community-survey-2018-22-estimates-by-m9gy-vc6p 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 cambridgema-gov/american-community-survey-2018-22-estimates-by-m9gy-vc6p: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 cambridgema-gov/american-community-survey-2018-22-estimates-by-m9gy-vc6p: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, cambridgema-gov/american-community-survey-2018-22-estimates-by-m9gy-vc6p is just another Postgres schema.