MySQL plugin for Swift-Kuery framework

What's New



Support MySQL 8.0.16


APIDoc Build Status - Master macOS Linux Apache 2 Slack Status


MySQL plugin for the Swift-Kuery framework. It enables you to use Swift-Kuery to manipulate data in a MySQL database.

Swift version

The latest version of SwiftKueryMySQL requires Swift 4.0 or newer. You can download this version of the Swift binaries by following this link. Compatibility with other Swift versions is not guaranteed.

Install MySQL


brew install mysql
mysql.server start


sudo apt-get update
sudo apt-get install mysql-server libmysqlclient-dev pkg-config
sudo service mysql start


On macOS, regular swift commands can be used for build and test. Use the example command below for generating an Xcode project.

For example,

swift build
swift test
swift package generate-xcodeproj --xcconfig-overrides Config.xcconfig

On linux standard swift commands will also work provided your mysql installation is version 5.7 or greater. If using an earlier version of mysql add -Xcc -I/usr/include/mysql to swift commands to point the compiler at the mysql header files:

For example,

swift build -Xcc -I/usr/include/mysql/
swift test -Xcc -I/usr/include/mysql/

Add dependencies

Add the SwiftKueryMySQL package to the dependencies within your application’s Package.swift file. Substitute "x.x.x" with the latest SwiftKueryMySQL release.

.package(url: "https://github.com/IBM-Swift/SwiftKueryMySQL.git", from: "x.x.x")

Add SwiftKueryMySQL to your target's dependencies:

.target(name: "example", dependencies: ["SwiftKueryMySQL"]),

Import package

import SwiftKueryMySQL

Using SwiftKueryMySQL

Create an instance of MySQLConnection by calling:

let connection = MySQLConnection(host: host, user: user, password: password, database: database,
                                 port: port, characterSet: characterSet)


  • host - hostname or IP of the MySQL server, defaults to localhost
  • user - the user name, defaults to current user
  • password - the user password, defaults to no password
  • database - default database to use, if specified
  • port - port number for the TCP/IP connection if connecting to server on a non-standard port (i.e. not 3306)
  • characterSet - MySQL character set to use for the connection

All the connection parameters are optional, so if you were using a standard local MySQL server as the current user, you could simply use:

let connection = MySQLConnection(password: password)

password is also optional, but recommended.

Alternatively, call:

let connection = MySQLConnection(url: URL(string: "mysql://\(user):\(password)@\(host):\(port)/\(database)")!))

You now have a connection that can be used to execute SQL queries created using Swift-Kuery.

To connect to the server and execute a query:

connection.connect() { result in
    guard result.success else {
        // Connection unsuccessful
    // Connection succesful
    // Use connection
    connection.execute(query: query) { queryResult in
      guard queryResult.success else {
          // Check for Error and handle
      // Process queryResult

MySQLConnections should not be used to execute concurrent operations and therefore should not be shared across threads without proper synchronisation in place. It is recommended to use a connection pool if you wish to share connections between multiple threads as the connection pool will ensure your connection is not used concurrently.

The example below creates a ConnectionPool containing a single connection and uses it to perform an insert on multiple threads:

var connectionPoolOptions = ConnectionPoolOptions.init(initialCapacity: 1, maxCapacity: 1)
let connectionPool = MySQLConnection.createPool(host: host, user: user, password: password, database: database, port: port, characterSet: nil, connectionTimeout: 10000, poolOptions: connectionPoolOptions)
let insertQuery = Insert(into: infos, values: "firstname", "surname", Parameter())
let insertGroup = DispatchGroup()
for age in 0 ... 5 {
    connectionPool.getConnection() { connection, error in
        guard let connection = connection else {
            // Error Handling and return
        connection.execute(query: insertQuery, parameters: [age]) { result in
            guard result.success else {
                // Error handling and return
            print("Successfully inserted age: \(age)")
            return insertGroup.leave()

When executing this example code you see output similar to:

Successfully inserted age: 0
Successfully inserted age: 1
Successfully inserted age: 2
Successfully inserted age: 3
Successfully inserted age: 4
Successfully inserted age: 5

This is because the connection pool only allows that connection to be obtained by a single task. Because the connection pool is now empty, additional tasks are queued for later execution. As each task completes, the single connection is returned to the pool, and the next task is then invoked.

In the example above, a DispatchGroup is used to pause the main thread until all of the tasks complete. This is necessary because the call to connectionPool.getConnection() returns immediately - the task is invoked later, once a connection is available.

If you increase the capacity of the thread pool, then the order of inserts will be unpredictable, as they are able to execute concurrently on different connections:

Successfully inserted age: 0
Successfully inserted age: 1
Successfully inserted age: 3
Successfully inserted age: 2
Successfully inserted age: 5
Successfully inserted age: 4

View the Swift-Kuery documentation for detailed information on using the Swift-Kuery framework.

For testing purposes - MySQL test setup

To run swift test to validate your MySQL installation, you must first run the following commands to set up your MySQL:

mysql_upgrade -uroot || echo "No need to upgrade"
mysql -uroot -e "CREATE USER 'swift'@'localhost' IDENTIFIED BY 'kuery';"
mysql -uroot -e "CREATE DATABASE IF NOT EXISTS test;"
mysql -uroot -e "GRANT ALL ON test.* TO 'swift'@'localhost';"

API Documentation

For more information visit our API reference.


We love to talk server-side Swift, and Kitura. Join our Slack to meet the team!

Deployment via Cloud Foundry

If you include SwiftKueryMySQL as a dependancy in an application you are deploying using the Cloud Foundry Swift buildpack then you will need to specify some additional flags when compiling your application. This is best achieved by adding a file to the root of your application named .swift-build-linux-options with the content:

$ cat .swift-build-options-linux 
-Xcc -I/usr/include/mysql/

These flags tell the compiler where to find the MySQL header files required to build the CMySQL library.


This library is licensed under Apache 2.0. Full license text is available in LICENSE.


  • Swift Tools 5.0.0
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Last updated: Thu Jun 27 2024 06:48:51 GMT-0900 (Hawaii-Aleutian Daylight Time)