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 all_city_funds table in this repository, by referencing it like:
"controllerdata-lacity/all-city-funds-ej7u-di9z:latest"."all_city_funds"or in a full query, like:
SELECT
":id", -- Socrata column ID
"other_cash_changes", -- Net of other transactions that increase or decrease the cash balance
"general_fund_reversion", -- Is the fund subject to General Fund reversion?
"fund_effective_date", -- Fund effective since
"fund_number", -- Financial Management System fund number
"current_cash_balance", -- Cash Balance
"capital_project", -- Does this Fund have any Capital Projects?
"grant_project", -- Is the fund associated with a grant?
"last_expense_recorded", -- Last expense transaction recorded
"assets", -- (A) Total Assets include Cash, Grant Receivables, and Other Assets
"cash_expenses", -- Cash disbursed in the current fiscal year
"fund_category", -- General Fund, Special Fund, or Proprietary
"interest_to_general_fund", -- Interest eligible for the General Fund?
"fund_type", -- Agency, Capital Projects, Debt Service, Enterprise, General Fund, Pension Trust, General Long Term Debt Group, or Special Revenue
"function", -- Arts/Culture/Tourism, Debt Service, Economic Development, Sanitation & Environment, Other, Housing & Homelessness, Parks, Public Safety, Public Works, Social Services, Streets, or Transportation
"contact_email", -- Contact's email address
"collected_revenue", -- Revenue collected in the current fiscal year
"fund_name", -- Financial Management System fund name
"administering_department", -- Department administering the fund
"fund_purpose", -- Purpose and intent of the fund
"budget_amendments", -- Amendments to the budget adopted by the Mayor and City Council
"liabilities", -- (B) Total Liabilities against the fund
"fund_balance", -- (C) where (C=A-B) - Total Assets minus Total Liabilities
"replacement_of_general_funds_allowed", -- Replacement of General Fund is allowed
"council_file_number", -- City Council file number authorizing the fund
"ordinance_number", -- Ordinance number used to establish the fund
"code_section", -- Administrative Code section
"budget_schedule_number", -- Funds with a schedule number have revenue and expenditure budgets reviewed and approved by the Mayor and City Council. Funds without a schedule number are considered "off-budget" since their budgets are not reviewed and approved by the Mayor and City Council.
"budget_schedule_name", -- Name of the budget schedule found in the City's budget
"council_district", -- City Council District
"contact_name", -- Departmental contact name
"contact_telephone", -- Contact's telephone number
"total_budget", -- Total budget
"beginning_cash", -- Beginning cash balance for the fiscal year
"fund_group", -- Fiduciary, Governmental, or Proprietary
"overhead_costs_reimbursement_eligibility", -- Fund is subject to overhead reimbursement costs
"inactive_fund_close", -- Is this an inactive fund? Default is no
"adopted_budget", -- Budget adopted by the Mayor and City Council
"sources_of_funds", -- Revenue source for this fund
"eligible_uses", -- Eligible uses for the fund
"council_file_link" -- Council file link information
FROM
"controllerdata-lacity/all-city-funds-ej7u-di9z:latest"."all_city_funds"
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 controllerdata-lacity/all-city-funds-ej7u-di9z with SQL in under 60 seconds.
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, 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 (like this repository), where the author has pushed Splitgraph Images to the repository, you can "clone" and/or "checkout" the data using sgr cloneand sgr checkout.
Cloning Data
Because controllerdata-lacity/all-city-funds-ej7u-di9z:latest is a Splitgraph Image, you can clone the data from Spltgraph Cloud to your local engine, where you can query it like any other Postgres database, using any of your existing tools.
First, install Splitgraph if you haven't already.
Clone the metadata with sgr clone
This will be quick, and does not download the actual data.
sgr clone controllerdata-lacity/all-city-funds-ej7u-di9zCheckout the data
Once you've cloned the data, you need to "checkout" the tag that you want. For example, to checkout the latest tag:
sgr checkout controllerdata-lacity/all-city-funds-ej7u-di9z:latestThis will download all the objects for the latest tag of controllerdata-lacity/all-city-funds-ej7u-di9z and load them into the Splitgraph Engine. Depending on your connection speed and the size of the data, you will need to wait for the checkout to complete. Once it's complete, you will be able to query the data like you would any other Postgres database.
Alternatively, use "layered checkout" to avoid downloading all the data
The data in controllerdata-lacity/all-city-funds-ej7u-di9z:latest is 0 bytes. If this is too big to download all at once, or perhaps you only need to query a subset of it, you can use a layered checkout.:
sgr checkout --layered controllerdata-lacity/all-city-funds-ej7u-di9z:latestThis will not download all the data, but it will create a schema comprised of foreign tables, that you can query as you would any other data. Splitgraph will lazily download the required objects as you query the data. In some cases, this might be faster or more efficient than a regular checkout.
Read the layered querying documentation to learn about when and why you might want to use layered queries.
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, controllerdata-lacity/all-city-funds-ej7u-di9z is just another Postgres schema.