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 report_card_assessment_data_201819_school_year table in this repository, by referencing it like:
"wa-gov/report-card-assessment-data-201819-school-year-5y3z-mgxd:latest"."report_card_assessment_data_201819_school_year"or in a full query, like:
SELECT
":id", -- Socrata column ID
"esdorganizationid", -- Educational Servce DIstrict ID
"percentparticipation", -- Percent of students that received a score
"percent_no_score", -- Percent of students that were not given a score
"percentmettestedonly", -- Percent of Students that met Standard (using only students that tested as denominator)
"percentlevel4", -- Percent of students that scored level 3: proficient
"percentlevel3", -- Percent of students that scored level 3: proficient
"percentlevel2", -- Percent of students that scored level 2: not proficient
"percentlevel1", -- Percent of students that scored level 1: not proficient
"percentmetstandard", -- A percent of students that met standard (CountMetStandard divided by Count of Students expected to test including previously passed)
"countmetstandard", -- Count of students expected to test (including students the previously passed the assessment)
"count_of_students_expected_to_test_including_previously_passed", -- Of the students that were expected to test, this is the count of students that met standard. Includes students that previously passed the assessment
"count_of_students_expected", -- Count of students expected to test (excluding students the previously passed the assessment)
"suppression", -- This field designates if suppression was applied to the row
"testsubject", -- Designates the tested subject: Science, English Language Arts (ELA), Science, ELPA, and WIDA
"testadministration", -- This field designates the assessment: Access to Instruction and Measurement (AIM), Smarter Ballance Assessment Consortium (SBAC), Washington Comprehensive Assessment of Science (WCAS), and English Learner Progress Assessment (ELPA)
"gradelevel",
"studentgroup", -- A subgroup of StudentGroupType. designates specific gender, race/ethnicity, or programs and characteristics associated with the data.
"studentgrouptype", -- Gender, Race/Ethnicity, Student Programs and Characteristics
"currentschooltype",
"schoolorganizationid", -- Unique school ID
"schoolname",
"schoolcode", -- Unique school code
"districtorganizationid", -- unique district ID
"districtname",
"districtcode", -- Unique district code
"test_administration_group", -- General, Alternate, or Other. This field designates the type of assessment General refers to the standard SBAC (ELA & Math) and WCAS (Science) assessments, Alternate designates the AIM (ELA, math, and science assessments), Other designates the English Learner Progress Assessment (ELPA)
"dataasof", -- Date data was extracted
"schoolyear", -- The school year the test was administered
"organizationlevel", -- This field designates if the data is for a school, district, or the state.
"county",
"esdname" -- Educational Servce DIstrict Name
FROM
"wa-gov/report-card-assessment-data-201819-school-year-5y3z-mgxd:latest"."report_card_assessment_data_201819_school_year"
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 wa-gov/report-card-assessment-data-201819-school-year-5y3z-mgxd with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.wa.gov. When you querywa-gov/report-card-assessment-data-201819-school-year-5y3z-mgxd: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.wa.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 \
"wa-gov/report-card-assessment-data-201819-school-year-5y3z-mgxd" \
--handler-options '{
"domain": "data.wa.gov",
"tables": {
"report_card_assessment_data_201819_school_year": "5y3z-mgxd"
}
}'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, wa-gov/report-card-assessment-data-201819-school-year-5y3z-mgxd is just another Postgres schema.