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 children_under_6_yrs_with_elevated_blood_lead table in this repository, by referencing it like:
"cityofnewyork-us/children-under-6-yrs-with-elevated-blood-lead-tnry-kwh5:latest"."children_under_6_yrs_with_elevated_blood_lead"or in a full query, like:
SELECT
":id", -- Socrata column ID
"children_under_6_years_with", -- Number of children less than 6 years old tested in a given year with blood lead levels of 5 mcg/dL or greater. The numbers in this table include all children tested within a given calendar year, regardless of whether they were tested in previous years with the same or different blood lead levels. While children can receive more than one test during the calendar year, children are only counted once using the highest confirmed blood lead level during the calendar year. If the child does not have a confirmed test in a given year, the child’s blood lead level is based on the highest capillary or unknown test type. This measure differs from the number of children newly identified with blood lead levels at or above a certain level reported by the Health Department in other publications. <a href="http://a816-dohbesp.nyc.gov/IndicatorPublic/EPHTPDF/Childhood_Lead_Exposure_Definitions_June_2016.pdf" target="_blank">Read more </a>about different measures used by the Health Department for surveillance of childhood lead poisoning.
"children_under_6_years_with_4", -- Number of children less than 6 years old tested in a given year with blood lead levels of 15 mcg/dL or greater. The numbers in this table include all children tested within a given calendar year, regardless of whether they were tested in previous years with the same or different blood lead levels. While children can receive more than one test during the calendar year, children are only counted once using the highest confirmed blood lead level during the calendar year. If the child does not have a confirmed test in a given year, the child’s blood lead level is based on the highest capillary or unknown test type. This measure differs from the number of children newly identified with blood lead levels of 15 mcg/dL or greater reported by the Health Department in other publications. <a href="http://a816-dohbesp.nyc.gov/IndicatorPublic/EPHTPDF/Childhood_Lead_Exposure_Definitions_June_2016.pdf" target="_blank">Read more </a>about different measures used by the Health Department for surveillance of childhood lead poisoning.
"children_under_6_years_with_6", -- Children under 6 years of age tested for lead poisoning in a given year. Children may be tested multiple times in a given year but are only counted once. All children are counted regardless of blood specimen type (confirmed or unconfirmed); the number is rounded to the nearest 100. <a href="http://a816-dohbesp.nyc.gov/IndicatorPublic/EPHTPDF/Childhood_Lead_Exposure_Definitions_June_2016.pdf" target="_blank">Read more </a>about different measures used by the Health Department for surveillance of childhood lead poisoning.
"children_under_6_years_with_8", -- Number of children less than 6 years old tested in a given year with blood lead levels of 5 mcg/dL or greater, divided by the total number of children less than 6 years old who were tested for lead poisoning in a given year; expressed as cases per 1,000 tested. The numbers in this table include all children tested within a given calendar year, regardless of whether they were tested in previous years with the same or different blood lead levels. While children can receive more than one test during the calendar year, children are only counted once using the highest confirmed blood lead level during the calendar year. If the child does not have a confirmed test in a given year, the child’s blood lead level is based on the highest capillary or unknown test type. This measure differs from the rate of children newly identified with blood lead levels at or above a certain level reported by the Health Department in other publications. <a href="http://a816-dohbesp.nyc.gov/IndicatorPublic/EPHTPDF/Childhood_Lead_Exposure_Definitions_June_2016.pdf" target="_blank">Read more </a>about different measures used by the Health Department for surveillance of childhood lead poisoning.
"children_under_6_years_with_9", -- Additional notes that apply to field above
"children_under_6_years_with_10", -- Number of children less than 6 years old tested in a given year with blood lead levels of 10 mcg/dL or greater, divided by the number of children less than 6 years old who were tested for lead poisoning in a given year; expressed as cases per 1,000 tested. The numbers in this table include all children tested within a given calendar year, regardless of whether they were tested in previous years with the same or different blood lead levels. While children can receive more than one test during the calendar year, children are only counted once using the highest confirmed blood lead level during the calendar year. If the child does not have a confirmed test in a given year, the child’s blood lead level is based on the highest capillary or unknown test type. This measure differs from the rate of children newly identified with blood lead levels at or above 10 mcg/dL reported by the Health Department in other publications. <a href="http://a816-dohbesp.nyc.gov/IndicatorPublic/EPHTPDF/Childhood_Lead_Exposure_Definitions_June_2016.pdf" target="_blank">Read more </a>about different measures used by the Health Department for surveillance of childhood lead poisoning.
"children_under_6_years_with_12", -- Number of children less than 6 years old tested in a given year with blood lead levels of 15 mcg/dL or greater, divided by the number of children less than 6 years old who were tested for lead poisoning in a given year; expressed as cases per 1,000 tested. The numbers in this table include all children tested within a given calendar year, regardless of whether they were tested in previous years with the same or different blood lead levels. While children can receive more than one test during the calendar year, children are only counted once using the highest confirmed blood lead level during the calendar year. If the child does not have a confirmed test in a given year, the child’s blood lead level is based on the highest capillary or unknown test type. This measure differs from the rate of children newly identified with blood lead levels of 15 mcg/dL or greater reported by the Health Department in other publications. <a href="http://a816-dohbesp.nyc.gov/IndicatorPublic/EPHTPDF/Childhood_Lead_Exposure_Definitions_June_2016.pdf" target="_blank">Read more </a>about different measures used by the Health Department for surveillance of childhood lead poisoning.
"children_under_6_years_with_13", -- Additional notes that apply to field above
"children_under_6_years_with_5", -- Additional notes that apply to field above
"children_under_6_years_with_11", -- Additional notes that apply to field above
"children_under_6_years_with_2", -- Number of children less than 6 years old tested in a given year with blood lead levels of 10 mcg/dL or greater. The numbers in this table include all children tested within a given calendar year, regardless of whether they were tested in previous years with the same or different blood lead levels. While children can receive more than one test during the calendar year, children are only counted once using the highest confirmed blood lead level during the calendar year. If the child does not have a confirmed test in a given year, the child’s blood lead level is based on the highest capillary or unknown test type. This measure differs from the number of children newly identified with blood lead levels of 10 mcg/dL or greater reported by the Health Department in other publications. <a href="http://a816-dohbesp.nyc.gov/IndicatorPublic/EPHTPDF/Childhood_Lead_Exposure_Definitions_June_2016.pdf" target="_blank">Read more </a>about different measures used by the Health Department for surveillance of childhood lead poisoning.
"time_period", -- The time period for which the data is aggregated; value could be a year, quarter, seasonal or multi-year
"children_under_6_years_with_7", -- Additional notes that apply to field above
"children_under_6_years_with_3", -- Additional notes that apply to field above
"geo_area_id", -- An ID for the geographic neighborhood of a given geography type
"geo_type", -- The type of geographic aggregation for the data; this could range from Citywide to Neighborhood Tabulation Areas in NYC.
"children_under_6_years_with_1", -- Additional notes that apply to field above
"geo_area_name", -- The neighborhood name for the geographic division
"borough_id" -- An ID for the NYC borough that the neighborhood falls within
FROM
"cityofnewyork-us/children-under-6-yrs-with-elevated-blood-lead-tnry-kwh5:latest"."children_under_6_yrs_with_elevated_blood_lead"
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 cityofnewyork-us/children-under-6-yrs-with-elevated-blood-lead-tnry-kwh5 with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.cityofnewyork.us. When you querycityofnewyork-us/children-under-6-yrs-with-elevated-blood-lead-tnry-kwh5: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.cityofnewyork.us, 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 \
"cityofnewyork-us/children-under-6-yrs-with-elevated-blood-lead-tnry-kwh5" \
--handler-options '{
"domain": "data.cityofnewyork.us",
"tables": {
"children_under_6_yrs_with_elevated_blood_lead": "tnry-kwh5"
}
}'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, cityofnewyork-us/children-under-6-yrs-with-elevated-blood-lead-tnry-kwh5 is just another Postgres schema.