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_interim_survey_in_the_zone
table in this repository, by referencing it like:
"usaid-gov/feed-the-future-malawi-interim-survey-in-the-zone-dwab-pz6j:latest"."feed_the_future_malawi_interim_survey_in_the_zone"
or in a full query, like:
SELECT
":id", -- Socrata column ID
"zoi", -- Was the data collected by Westat or ICF?
"e506a", -- What was the estimate total quantity of ITEM used? Quantity
"e506c", -- Did your household gather the ITEM , or did your household purchase or pay for the ITEM ?
"e504", -- ITEM
"s_hh_wt3", -- Household weights, adjusted for non-response, subgroup 3
"urbrur", -- Location type (urban rural)
"country", -- These data were collected in Malawi
"e508", -- FOR ITEMS THAT WERE BOUGHT: How much did you spend in total on ITEM ?
"today", -- The day of interview as a string variable, MM-DD-YYYY
"strata3", -- Stratification for subgroup 3
"pcc_wt3", -- Per capita consumption and poverty weight, subgroup 3
"e506b", -- What was the estimate total quantity of ITEM used? Unit
"cluster", -- Cluster number
"pbs_id", -- Administrative variable for identifying households
"ghht", -- Derived gendered household type
"project", -- Identifies whether the record is used to report on Feed the Future (FTF), Food for Peace (FFP), Catholic Relief Services (CRS), or Project Concern International (PCI) programming. Due to coordinated survey collection, the same record may be used to evalu
"e505", -- Over the past one year (12 months) did your household gather, purchase, or pay for any ITEM ? (NOTE THAT THE VALUE OF THESE ITEMS SHOULD BE ENTERED ONLY IF THEY WERE PURCHASED OR USED FOR HOUSEHOLD USE, NOT FOR INVESTMENT PURPOSES)
"survey", -- Two surveys were administered. This variable identifies whether the survey was the Interim Feed the Future survey or the Baseline Food for Peace survey.
"e507", -- FOR ITEMS THAT WERE GATHERED: What was the total estimated value of ITEM that you used?
"subgroup3" -- The 7-district FTF FEEDBACK ZOI which will include district level data from rural areas only of Michinji, Lilongwe, Dedza, Mangochi, Ntcheu, Balaka, Machinga.
FROM
"usaid-gov/feed-the-future-malawi-interim-survey-in-the-zone-dwab-pz6j:latest"."feed_the_future_malawi_interim_survey_in_the_zone"
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-interim-survey-in-the-zone-dwab-pz6j
with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.usaid.gov. When you queryusaid-gov/feed-the-future-malawi-interim-survey-in-the-zone-dwab-pz6j: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; sgr
can 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 clone
and sgr checkout
.
Mounting Data
This repository is an external repository. It's not hosted by Splitgraph. It is hosted by data.usaid.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 \
"usaid-gov/feed-the-future-malawi-interim-survey-in-the-zone-dwab-pz6j" \
--handler-options '{
"domain": "data.usaid.gov",
"tables": {
"feed_the_future_malawi_interim_survey_in_the_zone": "dwab-pz6j"
}
}'
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, usaid-gov/feed-the-future-malawi-interim-survey-in-the-zone-dwab-pz6j
is just another Postgres schema.