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dolt/docs/faq.md
Zach Musgrave dd5f99df1a Update faq.md
2021-07-30 16:55:06 -07:00

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# Dolt FAQ
## Why is it called Dolt? Are you calling me dumb?
It's named `dolt` to pay homage to [how Linus Torvalds named
git](https://en.wikipedia.org/wiki/Git#Naming):
> Torvalds sarcastically quipped about the name git (which means
> "unpleasant person" in British English slang): "I'm an egotistical
> bastard, and I name all my projects after myself. First 'Linux',
> now 'git'."
We wanted a word meaning "idiot", starting with D for Data,
short enough to type on the command line, and
not taken in the standard command line lexicon. So,
`dolt`.
## The MySQL shell gives me an error: `Can't connect to local MySQL server through socket '/tmp/mysql.sock'`
The MySQL shell will try to connect through a socket file on many OSes.
To force it to use TCP instead, give it the loopback address like this:
```bash
% mysql --host 127.0.0.1 ...
```
## What does `@@autocommit` do?
This is a SQL variable that you can turn on for your SQL session like so:
`SET @@autocommit = 1`
If it's set to a true value, then Dolt will flush your changes to disk
after every SQL statement, so that you can see your changes when you
run other commands (like `dolt diff`) from the command
line. Specifically, it updates the working set in your database state,
the same way that running `dolt sql -q ...` on the command line does.
Otherwise, you won't see changes outside your session until you issue
a `COMMIT` statement. See the next question.
## What's the difference between `COMMIT`, `COMMIT()`, and `DOLT_COMMIT()`?
`COMMIT` is a standard SQL statement that commits a transaction. In
dolt, it just flushes any pending changes in the current SQL session
to disk, updating the working set. HEAD stays the same, but your
working set changes. This means your edits will persist after this
session ends.
`COMMIT()` creates a new dolt commit, but doesn't reference it
anywhere. If you want to reference it, you have to take the value
returned by the function and create a branch with it (by inserting
into `dolt_branches`)
`DOLT_COMMIT()` is the same as if you run `dolt commit` from the
command line. It updates HEAD.
## I want each of my connected SQL users to get their own branch to make changes on, then merge them back into `master` when they're done making edits. How do I do that?
We are glad you asked! This is a common use case, and we wrote a
couple blog articles about how to do this effectively.
[dolt sql-server
concurrency](https://www.dolthub.com/blog/2021-03-12-dolt-sql-server-concurrency/)
[Merging and resolving conflicts programmatically with
SQL](https://www.dolthub.com/blog/2021-03-15-programmatic-merge-and-resolve/)
## Does Dolt support transactions?
Yes, it should exactly work the same as MySQL, but with fewer locks for competing writes.
It's also possible for different sessions to connect to different HEADs (branches) on
the same server. See [working with multiple heads](https://docs.dolthub.com/interfaces/sql/heads)
for details.
## What SQL features / syntax are supported?
Most of them! Check out [the docs for the full list of supported
features](https://docs.dolthub.com/interfaces/sql/sql-support).
You can check out what we're working on next on our
[roadmap](roadmap.md). Paying customers get their feature requests
bumped to the front of the line.
## Does Dolt support my favorite SQL workbench / tool?
Probably! Have you tried it? If you try it and it doesn't work, [let
us know with an issue](https://github.com/dolthub/dolt/issues) or in
[our Discord](https://discord.com/invite/RFwfYpu) and we'll see what
we can do. A lot of times we can fix small compatibility issues really
quick, like the same week. And even if we can't, we want to know about
it! Our goal is to be a 100% drop-in replacement for MySQL.