SQL
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DoltHub provides an API for accessing Dolt databases via web requests. A Dolt database can be attached to a DoltHub remote and pushed. At that point DoltHub provides an API against which users can execute Dolt SQL with results returned as JSON.
This shows our database metadata as a dictionary:
We can now execute a query:
This yields the results as JSON, with both schema and data:
As a reminder, this API is in Alpha version, and we will continue to flesh this out, as well as improve query performance, over time.
You can also explore our SQL API on DoltHub whenever you execute a query:
Since adding, updating, and deleting data can take a bit of time to execute against larger databases, we made the writable API asynchronous. Therefore we needed to add two HTTP endpoints for executing these kinds of queries using the SQL API.
First, we want to hit the write endpoint with our UPDATE query. This will start an asynchronous operation.
The main branch already exists in the database, and providing a <to_branch> that doesn't exist will create this new branch from the <from_branch>.
The yielded JSON results include an operation_name.
operation_name can be used to poll the second endpoint to check if the operation is done.
A done operation will yield a response that includes some query metadata, including from and to commit ids.
Since a lot of Dolt's functionality is exposed via SQL, we can use the commit ids to query the dolt_commit_diff_$tablename table to view the resulting diff from our UPDATE query.
We can repeat this process with as many queries as we want. Every query will create a commit on the <from_branch>.
Once we're satisfied with our changes, we can merge our branches by hitting the first endpoint with an empty query.
We will use an example DoltHub database, and the Python requests library to explore it in the Python console:
We can use our as an example. These are the steps we'd take to update a player's id in the player stats table.
You can learn more about using the writable SQL API .
The SQL query to execute.
SHOW TABLESThe name of the database owner.
dolthubThe name of the database.
ip-to-countryThe SQL query to execute.
SELECT * FROM IPv4ToCountry WHERE CountryCode2Letter = 'AU'The name of the database owner.
dolthubThe name of the database.
ip-to-countryThe database ref to execute the query against.
newbranchPoll the operation to check if the SQL write operation is done
The name of the database owner.
dolthubThe name of the database.
SHAQThe name of the operation
operations/72abb56b-d478-43ae-9a2d-c9602184c7abExecutes SQL write against to_branch (will be created from from_branch if it doesn't exist). If no query is provided, will merge to_branch into from_branch.
The name of the database owner.
dolthubThe name of the database.
SHAQThe base branch.
mainThe branch to write to. Will be created from the from_branch if it doesn't exist.
featureThe SQL query to execute. Use the request body instead for larger queries.
UPDATE player_season_stat_totals SET player_id=714287 WHERE player_id=15404617SQL write query to execute. Can be used in place of the query parameter for larger queries.
UPDATE player_season_stat_totals SET player_id=714287 WHERE player_id=15404617