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 educator_salary_distribution table in this repository, by referencing it like:
"delaware-gov/educator-salary-distribution-5tvj-rx46:latest"."educator_salary_distribution"or in a full query, like:
SELECT
":id", -- Socrata column ID
"gender", -- Represents the gender of the unique group of students within a school/district.
"grade", -- Represents the grade level of the unique group of students within a school/district.
"staffcount_salary_72k_79k", -- Represents number of staff who fall within the $72K - $79K salary range.
"staffcount_salary_93k_100k", -- Represents number of staff who fall within the $93K - $100K salary range.
"staffcount_salary_51k_58k", -- Represents number of staff who fall within the $51K - $58K salary range.
"subgroup", -- Names the unique group of educators within a school/district/state described by the combination of Race, Gender, Grade, SpecialDemo, and Geography.
"organization", -- Full name of the Organization which is the School if School Code is given in the row. Districtwide data rows give full name of School District. Statewide rows give "State of Delaware" in this column.
"staff_category", -- Represents a respective staff category that certain educators fall under, such as Classroom Teacher, Instructional Support, or Official/Administrative. For full list of staff categories and its subgroups, please see Appendix A in attached data dictionary.
"staffcount_salary_44k_51k", -- Represents number of staff who fall within the $44K - $51K salary range.
"race", -- Represents the race/ethnicity of the unique group of students within a school/district.
"staffcount_salary_65k_72k", -- Represents number of staff who fall within the $65K - $72K salary range.
"staffcount_salary_lt_30k", -- Represents number of staff who fall within the < $30K salary range.
"job_classification", -- Job classification category, such as Assistant Principal, Teacher, Special Secondary, or Librarian. For full list of job classifications, please see Appendix A in attached data dictionary.
"total", -- Represents a total number of staff who fall within salary ranges.
"staffcount_salary_gt_100k", -- Represents number of staff who fall within the > $100K salary range.
"staff_type", -- Staff type such as professional, non-professsional or all (both professional and non-professional)
"schoolyear", -- School year for which record is applicable. For example, 2019 = school year which ended in June 2019.
"districtcode", -- Number representing each School District. Statewide data rows will have “0” in this column.
"geography", -- Represents the geography of the unique group of students within a school/district.
"staffcount_salary_30k_37k", -- Represents number of staff who fall within the $30K - $37K salary range.
"staffcount_salary_37k_44k", -- Represents number of staff who fall within the $37K - $44K salary range.
"staffcount_salary_58k_65k", -- Represents number of staff who fall within the $58K - $65K salary range.
"staffcount_salary_86k_93k", -- Represents number of staff who fall within the $86K - $93K salary range.
"districtname", -- Full name of the School District. Statewide data rows have "State of Delaware" in this column.
"schoolcode", -- Number representing each School within the school district. Statewide or Districtwide data rows will have “0” in this column.
"staffcount_salary_79k_86k", -- Represents number of staff who fall within the $79K - $86K salary range.
"specialdemo" -- Represents the special population status of the unique group of students within a school/district.
FROM
"delaware-gov/educator-salary-distribution-5tvj-rx46:latest"."educator_salary_distribution"
LIMIT 100;Connecting to the DDN is easy. All you need is an existing SQL client that can connect to Postgres. As long as you have a SQL client ready, you'll be able to query delaware-gov/educator-salary-distribution-5tvj-rx46 with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.delaware.gov. When you querydelaware-gov/educator-salary-distribution-5tvj-rx46:latest on the DDN, we "mount" the repository using the socrata mount handler. The mount handler proxies your SQL query to the upstream data source, translating it from SQL to the relevant language (in this case SoQL).
We also cache query responses on the DDN, but we run the DDN on multiple nodes so a CACHE_HIT is only guaranteed for subsequent queries that land on the same node.
Query Your Local Engine
bash -c "$(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.delaware.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 \
"delaware-gov/educator-salary-distribution-5tvj-rx46" \
--handler-options '{
"domain": "data.delaware.gov",
"tables": {
"educator_salary_distribution": "5tvj-rx46"
}
}'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, delaware-gov/educator-salary-distribution-5tvj-rx46 is just another Postgres schema.