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 employment_wages_in_colorado table in this repository, by referencing it like:
"colorado-gov/employment-wages-in-colorado-busm-qa5b:latest"."employment_wages_in_colorado"or in a full query, like:
SELECT
":id", -- Socrata column ID
"stateabbrv", -- The two letter state abbreviation.
"statename", -- State name.
"stfips", -- State FIPS code.
"areaname", -- Geographic area name.
"areatype", -- Code describing type of geographic area: e.g. county, service delivery area, MSA.
"areatyname", -- Descriptive title of the areatype.
"area", -- Six-digit code assigned to represent a geographic area. Front fill with zeroes.
"periodyear", -- Character representation of calendar-year (e.g. 2000).
"periodtype", -- Code describing type of period (e.g. Annual, quarterly, monthly, etc.).
"pertypdesc", -- A description of the period type.
"period", -- Period code. Will be set to ‘00’ where periodtype is annual.
"indcodty", -- Code describing the industry code type.
"indcode", -- A code used in the classification of establishments by type of activity in which they are engaged. For codes not 6 characters long, left justify and blank (ASCII 32) fill. Either SIC or NAICS code can be used. A siccode of 9999 means non-classifiable; industry not specified.
"indcodetitle", -- The descriptive title for this industry code.
"occodetype", -- Code describing the type of occupational coding system.
"occodetydesc", -- Title of classification Code.
"occcode", -- The occupational classification code used by the state for this data element. This code could be a DOT, OES, SOC, CENSUS, etc. For codes not 10 characters long, left justify and blank (ASCII 32) fill.
"codetitle", -- The descriptive title for this occupation or training code.
"wagesource", -- A code representing the source of the wage data.
"wagesrdesc", -- A description of the source of the wage data.
"ratetype", -- Code which identifies the type of wage rate.
"ratetydesc", -- A description of the type of wage rate.
"empcount", -- Total employment.
"response", -- Response rate for the occupation’s actual or real survey data. Does NOT include imputed data in the rate calculation.
"mean", -- Mean wage for the occupation.
"entrywg", -- Entry level wage for the occupation, mean of the first third (ALC definition).
"experience", -- Experienced level wage for the occupation, mean of upper two thirds (ALC definition).
"pct10", -- Wage at tenth percentile.
"pct25", -- Wage at twenty-fifth percentile.
"median", -- Median wage of the occupation; also the wage at fiftieth percentile.
"pct75", -- Wage at seventy-fifth percentile.
"pct90", -- Wage at ninetieth percentile.
"udpct", -- User defined percentile.
"udpctwage", -- Wage at user defined percentile.
"udrnglopct", -- Low percentile for user defined range.
"udrnghipct", -- High percentile for user defined range.
"udrngmean", -- Mean wage for user defined range.
"wpctrelerr", -- Relative percent error on wage.
"epctrelerr", -- Relative percent error on employment.
"panelcode" -- Reference panel code (yyyymm)
FROM
"colorado-gov/employment-wages-in-colorado-busm-qa5b:latest"."employment_wages_in_colorado"
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 colorado-gov/employment-wages-in-colorado-busm-qa5b with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.colorado.gov. When you querycolorado-gov/employment-wages-in-colorado-busm-qa5b: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.colorado.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 \
"colorado-gov/employment-wages-in-colorado-busm-qa5b" \
--handler-options '{
"domain": "data.colorado.gov",
"tables": {
"employment_wages_in_colorado": "busm-qa5b"
}
}'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, colorado-gov/employment-wages-in-colorado-busm-qa5b is just another Postgres schema.