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 office_of_the_comptroller_teachers_retirement table in this repository, by referencing it like:
"cityofnewyork-us/office-of-the-comptroller-teachers-retirement-5u2d-n46s:latest"."office_of_the_comptroller_teachers_retirement"or in a full query, like:
SELECT
":id", -- Socrata column ID
"period_end_date", -- This column sets forth the end date of the fiscal year
"local_market_value", -- This column sets forth the average value of the investment in the investment’s local market as of the date set forth in the Period End Date column
"base_total_cost", -- This column sets forth the total cost basis of the investment
"major_industry_name", -- This column sets forth the major industry in which the investment falls
"investment_type_name", -- This column sets forth the name of the type of investment
"data_as_of",
"interest_rate", -- This column sets for the interest rate paid on the investment, if any.
"base_unrealized_gain_loss", -- This column sets forth the unrealized gain or loss in value of the investment since acquisition
"direct_group_trust_holding", -- Indicates a Direct or Group Trust Holding
"moody_s_quality_rating", -- This column sets forth the rating that has been assigned to the investment by Moody's, where a rating is available
"minor_industry_name", -- This column sets forth the minor industry in which the investment falls
"original_face", -- This column sets for the original face value of the investment instrument, if any
"base_accrued_interest", -- This column sets forth the amount of interest that has accrued on a fixed income investment since acquisition
"base_market_value", -- This column sets forth the average market value of the investment as of the date set forth in the Period End Date column
"shares_par_value", -- In the case of fixed income investments (such as bonds), this column sets forth the “par value,” or face value, of the investment instrument; in the case of stock and other financial instruments, this column sets forth the number of shares or units held
"s_and_p_quality_rating", -- This column sets forth the rating that has been assigned to the investment by S&P, where a rating is available
"local_unrealized_gain_loss", -- This column sets forth the unrealized gain or loss in value of the investment since acquisition in the investment’s local market
"asset_class", -- This column sets forth the investment category into which the investment falls (equity, fixed income, cash or cash equivalent)
"local_currency_code", -- This column sets forth the currency code of the country in which the security or financial instrument originates
"local_total_cost_amount", -- This column sets forth the total cost basis of the investment in the investment’s local market
"trade_country_name", -- This column lists the country from which the security or financial instrument originates
"security_name", -- This column sets forth the name of the security or financial instrument. In the case of stock and corporate bonds, this will be the company name or bond name. In the case of currency holdings, this will be the name of the currency. In the case of investment funds, it will be the name of the company operating the investment fund.
"security_description", -- This column provides a basic description of the security or financial investment, if any.
"maturity_date", -- This column sets forth the maturity date of the investment, if any.
"local_accrued_interest" -- This column sets forth the amount of interest that has accrued on a fixed income investment since acquisition in the investment’s local market
FROM
"cityofnewyork-us/office-of-the-comptroller-teachers-retirement-5u2d-n46s:latest"."office_of_the_comptroller_teachers_retirement"
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/office-of-the-comptroller-teachers-retirement-5u2d-n46s 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 cityofnewyork-us/office-of-the-comptroller-teachers-retirement-5u2d-n46s: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 cityofnewyork-us/office-of-the-comptroller-teachers-retirement-5u2d-n46sCheckout 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 cityofnewyork-us/office-of-the-comptroller-teachers-retirement-5u2d-n46s:latestThis will download all the objects for the latest tag of cityofnewyork-us/office-of-the-comptroller-teachers-retirement-5u2d-n46s 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 cityofnewyork-us/office-of-the-comptroller-teachers-retirement-5u2d-n46s: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 cityofnewyork-us/office-of-the-comptroller-teachers-retirement-5u2d-n46s: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, cityofnewyork-us/office-of-the-comptroller-teachers-retirement-5u2d-n46s is just another Postgres schema.