code: function MssqlCrLayer(config) {
    if (!(this instanceof MssqlCrLayer)) {
      return new MssqlCrLayer(config)
    }
    const mssqlConfig = toMssqlConfig(config)
    connectionParams.set(this, mssqlConfig)
    this.user = mssqlConfig.user
    this.database = mssqlConfig.database
    this.host = mssqlConfig.server
    this.port = mssqlConfig.port
    this.ISOLATION_LEVEL = (config && config.ISOLATION_LEVEL) || 'READ_COMMITTED'
  }
docs: SQL Server common requests interface layer
  
  @param config {object}
  user: <username>,
  password: <password>,
  host: <host>,
  pool: {
  max: <max pool size>,
  idleTimeout: <idle timeout in milliseconds>
  }
  
  @returns {MssqlCrLayer}
  @constructor