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99 lines
2.9 KiB
Markdown
99 lines
2.9 KiB
Markdown
## Purpose:
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The db.mysql module can be used to develop software that connects to the popular open source
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MySQL or MariaDB database servers.
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### Local setup of a development server:
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To run the mysql module tests, or if you want to just experiment, you can use the following
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command to start a development version of MySQL using docker:
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```sh
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docker run -p 3306:3306 --name some-mysql -e MYSQL_ALLOW_EMPTY_PASSWORD=1 -e MYSQL_ROOT_PASSWORD= -d mysql:latest
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```
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The above command will start a server instance without any password for its root account,
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available to mysql client connections, on tcp port 3306.
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You can test that it works by doing: `mysql -uroot -h127.0.0.1` .
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You should see a mysql shell (use `exit` to end the mysql client session).
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Use `docker container stop some-mysql` to stop the server.
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Use `docker container rm some-mysql` to remove it completely, after it is stopped.
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### Installation of development dependencies:
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For Linux, you need to install `MySQL development` package and `pkg-config`.
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For Windows, install [the installer](https://dev.mysql.com/downloads/installer/) ,
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then copy the `include` and `lib` folders to `<V install directory>\thirdparty\mysql`.
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### Troubleshooting
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If you encounter weird errors (your program just exits right away, without
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printing any messages, even though you have `println('hi')` statements in your
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`fn main()`), when trying to run a program that does `import db.mysql` on windows, you
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may need to copy the .dll file: `thirdparty/mysql/lib/libmysql.dll`, into the folder
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of the executable too (it should be right next to the .exe file).
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This is a temporary workaround, until we have a more permanent solution, or at least
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more user friendly errors for that situation.
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## Basic Usage
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```v oksyntax
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import db.mysql
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// Create connection
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config := mysql.Config{
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host: '127.0.0.1'
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port: 3306
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username: 'root'
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password: '12345678'
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dbname: 'mysql'
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}
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// Connect to server
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mut db := mysql.connect(config)!
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// Do a query
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res := db.query('select * from users')!
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rows := res.rows()
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for row in rows {
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println(row.vals)
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}
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// Close the connection if needed
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db.close()
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```
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## Transaction
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```v oksyntax
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import db.mysql
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// Create connection
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config := mysql.Config{
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host: '127.0.0.1'
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port: 3306
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username: 'root'
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password: '12345678'
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dbname: 'mysql'
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}
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mut db := mysql.connect(config)!
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// turn off `autocommit` first
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db.autocommit(false)!
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// begin a new transaction
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db.begin()!
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mut result_code := db.exec_none('insert into users (username) values ("tom")')
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assert result_code == 0
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// make a savepoint
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db.savepoint('savepoint1')!
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result_code = db.exec_none('insert into users (username) values ("kitty")')
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assert result_code == 0
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// rollback to `savepoint1`
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db.rollback_to('savepoint1')!
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result_code = db.exec_none('insert into users (username) values ("mars")')
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assert result_code == 0
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db.commit()!
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res := db.query('select * from users')!
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rows := res.rows()
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dump(rows)
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// Close the connection if needed
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db.close()
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```
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