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 feed_the_future_malawi_baseline_household_survey table in this repository, by referencing it like:
"usaid-gov/feed-the-future-malawi-baseline-household-survey-a4ce-qaef:latest"."feed_the_future_malawi_baseline_household_survey"or in a full query, like:
SELECT
":id", -- Socrata column ID
"zia_visit2_yn", -- ZIA Visit2 yn
"f06", -- ZIF Whl day no eat freq
"hhhunger", -- Moderate or Severe HH Hunger
"hungerscale", -- Household Hunger Scale 0 6
"d04", -- ZID Rooms num
"country", -- ZIA Country
"modf_missing", -- Missing all elements from F
"d06", -- ZID Drink water src
"f03", -- ZIF Sleep hungry yn
"a21", -- Interview outcome derived by module C data
"hhwght", -- Household weight
"zid_drink_water_src_other", -- ZID Drink water src other specify
"zid_roof_tp_oth_sp", -- ZID Roof tp oth sp
"zid_fuel_src_2", -- ZID Fuel src 2
"d05", -- ZID Toilet tp
"modd_missing", -- Missing all elements from D
"pbs_id", -- PBS ID
"d03", -- ZID Ext wall tp
"d02", -- ZID Floor tp
"d01", -- ZID Roof tp
"zi_start_dt", -- ZI Start DT
"zia_visit2_rsn", -- ZIA Visit2 rsn
"f02", -- ZIF No food freq
"zid_floor_tp_oth_sp", -- ZID Floor tp oth sp
"a06", -- Household type derived by module C data
"zid_drink_water_src_other_1", -- ZID Drink water src other specify 2
"zia_visit2_dt", -- ZIA Visit2 dt
"d07", -- ZID Electr yn
"f04", -- ZIF Sleep hungry freq
"zid_fuel_src_oth_sp", -- ZID Fuel src oth sp
"urbrur", -- Urban Rural 1 urban 2 rural
"zid_toilet_tp_oth_sp", -- ZID Toilet tp oth sp
"a02", -- ZIA Cluster cd
"zia_supervisor_cd", -- ZIA Supervisor cd
"zia_location_cd", -- ZIA Location cd
"a09", -- Household type derived by module C data
"zid_electr_yn_2", -- ZID Electr yn 2
"zid_ext_wall_tp_oth_sp", -- ZID Ext wall tp oth sp
"d08", -- ZID Fuel src
"a05", -- ZIG1 Sex g1
"f01", -- ZIF No food yn
"zid_drink_water_src_2", -- ZID Drink water src 2
"f05", -- ZIF Whl day no eat yn
"hh_size" -- HouseHold Size
FROM
"usaid-gov/feed-the-future-malawi-baseline-household-survey-a4ce-qaef:latest"."feed_the_future_malawi_baseline_household_survey"
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 usaid-gov/feed-the-future-malawi-baseline-household-survey-a4ce-qaef 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 usaid-gov/feed-the-future-malawi-baseline-household-survey-a4ce-qaef: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 usaid-gov/feed-the-future-malawi-baseline-household-survey-a4ce-qaefCheckout 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 usaid-gov/feed-the-future-malawi-baseline-household-survey-a4ce-qaef:latestThis will download all the objects for the latest tag of usaid-gov/feed-the-future-malawi-baseline-household-survey-a4ce-qaef 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 usaid-gov/feed-the-future-malawi-baseline-household-survey-a4ce-qaef: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 usaid-gov/feed-the-future-malawi-baseline-household-survey-a4ce-qaef: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, usaid-gov/feed-the-future-malawi-baseline-household-survey-a4ce-qaef is just another Postgres schema.