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 april_2021_mixed_topic_survey_length_edmonton table in this repository, by referencing it like:
"edmonton-ca/april-2021-mixed-topic-survey-length-edmonton-7gkt-aapc:latest"."april_2021_mixed_topic_survey_length_edmonton"or in a full query, like:
SELECT
":id", -- Socrata column ID
"q9a_edmonton_study_profiling_questionnaire_2014", -- Profiling question, one response selected by respondent. - How long have you lived in Edmonton? Possible Answers: Less than 1 year/Between 1 to 2 years/Between 3 to 5 years/Greater than 5 years/I do not live in Edmonton
"q8_born_canada_study_profiling_questionnaire_2014", -- Profiling question, one response selected by respondent. - Were you born in Canada? Possible Answers: Yes/No
"q3_own_rent_study_profiling_questionnaire_2014", -- Profiling question, one response selected by respondent. - Do you own or rent your primary residence in the City of Edmonton? Possible Answers: Own/Rent
"q13_volunteer_study_profiling_questionnaire_2014", -- Profiling question, one response selected by respondent. - In the last 12 months, did you do any activities without pay on behalf of a group or an organization as a volunteer? Possible Answers: Yes/No
"gender_study_profiling_questionnaire_2014", -- Profiling question, one response selected by respondent. - Are you? Possible Answers: Male/Female/Other/I prefer not to answer
"age_rollup_detailed_study_profiling_questionnaire_2014", -- Profiling question, Based on birthdate entered by Respondent. System Determined. Question: Age Rollup? - Possible Answers: Under 15/15-17/18-24/25-29/30-34/35-39/40-44/45-49/50-54/55-59/60-64/65-69/70-74/75-79/80 and over
"browsertype", -- System Captured, Browser used by the respondent. Question: Browser Type? - BrowserType Possible Answers: Internet Explorer/Firefox/Safari/Google Chrome/Opera/Android/BlackBerry/Unknown
"survey_q3", -- Respondents were then asked, “At what duration do you feel the survey starts feeling long, but you would still complete it?” Possible answers were: 1 minute 2 minutes 3 minutes 4 minutes 5 minutes 6 minutes 7 minutes 8 minutes 9 minutes 10 minutes 11 minutes 12 minutes 13 minutes 14 minutes 15 minutes 16 minutes 17 minutes 18 minutes 19 minutes 20+ minutes
"completeddate", -- Date/Time the respondent finished the survey.
"responsedate",
"q17_city_employee_study_profiling_questionnaire_2014", -- Profiling question, one response selected by respondent. - Do you work for the City of Edmonton? Possible Answers: Yes/No/Prefer not to say
"q16_education_study_profiling_questionnaire_2014", -- Profiling question, one response selected by respondent. - What is the highest level of education you have completed? Possible Answers: Elementary/grade school graduate/High school graduate/College / technical school graduate/University undergraduate degree/Post-graduate degree/Professional school graduate (e.g. medicine, dentistry, veterinary medicine, optometry)
"q15_household_income_study_profiling_questionnaire_2014", -- Profiling question, one response selected by respondent. - Which of the following categories best describes your total household income in 2014 before taxes? Possible Answers: Under $20,000/$20,000 to $29,999/$30,000 to $39,999/$40,000 to $49,999/$50,000 to $59,999/$60,000 to $79,999/$80,000 to $99,999/$100,000 to $149,000/$150,000 and over/Prefer not to answer
"q14a_primary_transportation_study_profiling_questionnaire_2014", -- Profiling question, one response selected by respondent. - What is your primary mode of transportation? Possible Answers: Car/truck/Van as DRIVER/Car/truck/van as PASSENGER/Public Transit/Walk/Bicycle/Other (Specify)
"q12_employment_status_study_profiling_questionnaire_2014", -- Profiling question, one response selected by respondent. - What is your current employment status? Possible Answers: Employed full-time (30+ hours a week)/Employed part-time (0-30 hours a week)/Homemaker/Post-secondary student/High School Student/Unemployed/Permanently unable to Work/Retired/Other (Specify)
"q11_home_language_study_profiling_questionnaire_2014", -- Profiling question, one response selected by respondent. - What is the primary language spoken in your household? Possible Answers: English/Arabic/Cantonese/Spanish/Panjabi (Punjabi)/French/German/Mandarin/Tagalog (Pilipino, Filipino)/Ukrainian/Other (Specify)
"fsa_study_profiling_questionnaire_2014", -- Forward Sortation Area (first 3 characters of postal code)
"ostype", -- System Captured, OS used by the respondent. Question: OS Type? - OSType Possible Answers: Mac (OS X)/Linux/Windows/iOS/Android/BlackBerry/Unknown
"survey_q4", -- Respondents were then asked, “At what duration do you feel the survey is really very long and you are very unlikely to complete it?” Possible answers were: 1 minute 2 minutes 3 minutes 4 minutes 5 minutes 6 minutes 7 minutes 8 minutes 9 minutes 10 minutes 11 minutes 12 minutes 13 minutes 14 minutes 15 minutes 16 minutes 17 minutes 18 minutes 19 minutes 20+ minutes
"survey_q1", -- In the February 2021 Mixed Topic Survey, we had asked you about what makes you more likely to respond to a survey. Length of the survey or the time it takes to complete the survey were the top factors. We would like to know more about your preferred duration of the survey. Imagine there is a survey sent to you on a topic of your interest and relevant to you. Respondents were asked “At what duration do you feel the survey is so short that it is not providing you enough opportunities to share your thoughts?" Possible answers were: 1 minute 2 minutes 3 minutes 4 minutes 5 minutes 6 minutes 7 minutes 8 minutes 9 minutes 10 minutes 11 minutes 12 minutes 13 minutes 14 minutes 15 minutes 16 minutes 17 minutes 18 minutes 19 minutes 20+ minutes
"starteddate", -- Date/Time the respondent first opened/started the survey.
"index",
"survey_q2", -- Respondents were then asked, “At what duration do you feel the survey is just the right length for you to share your thoughts and also does not take too much time for you to complete?” Possible answers were: 1 minute 2 minutes 3 minutes 4 minutes 5 minutes 6 minutes 7 minutes 8 minutes 9 minutes 10 minutes 11 minutes 12 minutes 13 minutes 14 minutes 15 minutes 16 minutes 17 minutes 18 minutes 19 minutes 20+ minutes
"q7_children_study_profiling_questionnaire_2014", -- Profiling question, one response selected by respondent. - Do you have children 18 or under living at home? Possible Answers: Yes/No
"q14b_secondary_transportation_study_profiling_questionnaire_201", -- Profiling question, one response selected by respondent. - What is your secondary mode of transportation? Possible Answers: Car/truck/Van as DRIVER/Car/truck/van as PASSENGER/Public Transit/Walk/Bicycle/Only have one mode of transportation/Other (Specify)
"devicetype", -- System Captured, Device used by the respondent. Question: Device Type? - DeviceType Possible Answers: Tablet/Desktop/Phone
"q10_own_business_study_profiling_questionnaire_2014" -- Profiling question, one response selected by respondent. - Do you own a business in the City of Edmonton? Possible Answers: Yes/No
FROM
"edmonton-ca/april-2021-mixed-topic-survey-length-edmonton-7gkt-aapc:latest"."april_2021_mixed_topic_survey_length_edmonton"
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 edmonton-ca/april-2021-mixed-topic-survey-length-edmonton-7gkt-aapc with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.edmonton.ca. When you queryedmonton-ca/april-2021-mixed-topic-survey-length-edmonton-7gkt-aapc: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.edmonton.ca, 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 \
"edmonton-ca/april-2021-mixed-topic-survey-length-edmonton-7gkt-aapc" \
--handler-options '{
"domain": "data.edmonton.ca",
"tables": {
"april_2021_mixed_topic_survey_length_edmonton": "7gkt-aapc"
}
}'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, edmonton-ca/april-2021-mixed-topic-survey-length-edmonton-7gkt-aapc is just another Postgres schema.