Basic mysql bindings for crystal.
Crystal Shell
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README.md

crystal-mysql

Build Status

Fork of https://github.com/farleyknight/crystal-mysql

Basic MySQL bindings for Crystal.

CAUTION: Pre-alpha quality. Don't use for anything serious. Any bug reports and feedback are warmly welcome!

Installation

Add it to your shard.yml

dependencies:
  mysql:
    github: waterlink/crystal-mysql
    version: ~> 0.4

Usage

require "mysql"

Connecting to mysql

# MySQL.connect(host, user, password, database, port, socket, flags = 0)
conn = MySQL.connect("127.0.0.1", "crystal_mysql", "", "crystal_mysql_test", 3306_u16, nil)

Making a query

conn.query(%{SELECT 1})  #=> [[1]]

conn.query(%{CREATE TABLE user (id INT, email VARCHAR(255), name VARCHAR(255))})

conn.query(%{INSERT INTO user(id, email, name) values(1, "john@example.com", "John Smith")})
conn.query(%{INSERT INTO user(id, email, name) values(2, "sarah@example.com", "Sarah Smith")})

conn.query(%{SELECT * FROM user}) #=> [[1, "john@example.com", "John Smith"], [2, "sarah@example.com", "Sarah Smith"]]

conn.query(%{DROP TABLE user})

Using higher level Query api

MySQL::Query
  .new(%{SELECT * FROM user WHERE created_at > :from_filter},
       { "from_filter" => 14.days.ago })
  .run(conn)

You can reference parameters in query with symbol-like syntax: :some_symbol_like_syntax or :someSymbolLikeSyntax. And then you can resolve these references with passing a hash as a second argument, which specifies values for these parameters.

By the way all strings get properly escaped, so no SQL injections should be possible (if something is not escaped properly, then it is a bug, and you should probably report it here on github).

You can reference the same symbol multiple times in one query, as well you can use as much symbols as you want.

Making a transaction

other_conn = MySQL.connect("127.0.0.1", "crystal_mysql", "", "crystal_mysql_test", 3306_u16, nil)

conn.transaction do
  conn.query(%{SELECT COUNT(id) FROM user})  #=> 2
  conn.query(%{INSERT INTO user(id, email, name) values(1, "james@example.com", "James Smith")})

  conn.query(%{SELECT COUNT(id) FROM user})  #=> 3
  other_conn.query(%{SELECT COUNT(id) FROM user})  #=> 2
end

conn.query(%{SELECT COUNT(id) FROM user})  #=> 3
other_conn.query(%{SELECT COUNT(id) FROM user})  #=> 3

If block provided for #transaction raises exception, then it will rollback transaction automatically.

You can use #start_transaction, #commit_transaction and #rollback_transaction manually:

begin
  conn.start_transaction
  # .. do stuff with conn ..
  conn.commit_transaction
rescue
  conn.rollback_transaction
end

Nested transactions are possible.

Closing connection

conn.close

Notes

  • This library assumes tinyint is used as boolean type.

High-level API roadmap

High level method Implemented?
MySQL.connect Yes
Connection#initialize Yes
Connection#client_info Yes
Connection#error Yes
Support#escape_string Yes
Connection#connect Yes
Connection#host_info No
Connection#query 72% (usable)
Connection#start_transaction Yes
Connection#commit_transaction Yes
Connection#rollback_transaction Yes
Connection#transaction Yes
Connection#close Yes
Query#to_mysql Yes
Query#run Yes

TODO

  • Support more types: Enum, Set, Geometry, Binary strings
  • Figure out utf-8 (and other collations) support
  • Set up CI for different versions of mysql, ie: 5.5, 5.6, 5.7
  • Set up CI for mac os x
  • Figure out 32bit support?

Contributing

  1. Fork it ( https://github.com/waterlink/crystal-mysql/fork )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request

Contributors