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 street_range table in this repository, by referencing it like:
"brla-gov/street-range-fisq-xxsz:latest"."street_range"or in a full query, like:
SELECT
":id", -- Socrata column ID
"to_add_right", -- Street segment runs to this address at the right
"st_end_meas_sf", -- Louisiana DOTD linear referencing system (LRS) end measurement (in feet)
"lrs_id", -- Louisiana DOTD linear referencing system (LRS) identication number
"modified_date", -- Date the street segment was last edited (if applicable)
"cad_ftc", -- Census FCC
"st_begin_meas_sf", -- Louisiana DOTD linear referencing system (LRS) begin measurement (in feet)
"street_incept_date", -- Date the street segment was established
"jurisdiction", -- Jurisdiction where the road segment is (if applicable)
"data_source", -- Source of the data
"emergency_funding", -- Emergency funding for the street segment (if applicable)
"alt_federal_route", -- Alternate federal route (if applicable)
"federal_route_type", -- Federal route type (if applicable)
"curb", -- Side(s) of the street segment with a curb and gutter
"st_owner", -- Owner of the street segment
"community_left", -- Community on the left side of the street segment
"created_date", -- Date the street segment was created (if applicable)
"st_directional", -- Street direction
"st_segment_num", -- Street segment number
"private_street", -- Street segment is on a private street (Yes or No)
"alt_state_route_type", -- Alternate state route type (if applicable)
"state_route_type", -- State route type (if applicable)
"community_right", -- Community on the right side of the street segment
"zip_code_right", -- ZIP code on the right side of the street segment
"postal_community_left", -- Postal community on the left side of the street segment
"subdivision", -- Subdivision where the road segment is (if applicable)
"to_elevation_level", -- Street segment runs from elevation level (0-1)
"one_way_direction", -- Direction of the one-way street segment (if applicable)
"restricted_access", -- Access restriction (Yes or No)
"from_add_right", -- Street segment runs from this address at the right
"to_add_left", -- Street segment runs to this address at the left
"number_lanes",
"parish_name_right", -- Parish on the right side of the street segment
"parish_name_left", -- Parish on the left side of the street segment
"notation", -- Additional notes regarding this street segment (if applicable)
"state_route", -- State route (if applicable)
"alt_federal_route_type", -- Alternate federal route type (if applicable)
"federal_route", -- Federal route (if applicable)
"speed_mph", -- Speed limit of the street segment (miles per hour)
"shoulder", -- Side(s) of the street segment with a shoulder
"drainage_maint_responsibility", -- Drainage maintenance responsibility for the street segment
"zip_code_left", -- ZIP code on the left side of the street segment
"postal_community_right", -- Postal community on the right side of the street segment
"road_type", -- Type of road
"road_class", -- Class of road
"from_elevation_level", -- Street segment runs from elevation level (0-1)
"one_way", -- Pattern of traffic relative to direction of street segment digitization. (B = traffic runs both directions, F = traffic runs same direction as digitization, T = traffic runs opposite direction as digitization). Most centerlines are digitized south to north, or west to east.
"st_type", -- Type of street
"parity_left", -- Description of the block range on the left side of the street segment (E = even, O = odd, and Z = no range)
"from_add_left", -- Street segment runs from this address at the left
"street_name_complete", -- Street name
"st_name_id", -- Street name ID
"st_segment_id", -- Street segment ID
"st_elevation_level", -- Street elevation level (0-3)
"truck_route", -- Street segment is a truck route (Yes or No)
"priority_to_keep_open", -- Priority to keep this street segment open
"alt_state_route", -- Alternate state route (if applicable)
"the_geom", -- Line geometry of the street range segment
"parity_right" -- Description of the block range on the right side of the street segment (E = even, O = odd, and Z = no range)
FROM
"brla-gov/street-range-fisq-xxsz:latest"."street_range"
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 brla-gov/street-range-fisq-xxsz 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 brla-gov/street-range-fisq-xxsz: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 brla-gov/street-range-fisq-xxszCheckout 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 brla-gov/street-range-fisq-xxsz:latestThis will download all the objects for the latest tag of brla-gov/street-range-fisq-xxsz 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 brla-gov/street-range-fisq-xxsz: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 brla-gov/street-range-fisq-xxsz: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, brla-gov/street-range-fisq-xxsz is just another Postgres schema.