Method setPrecision

src/backend/kernel.js:569–572

* Set precision to 'unsigned' or 'single' * @param {String} flag 'unsigned' or 'single' * @return {this}

(flag)

   * @return {this}
   */
  setPrecision(flag) {
    this.precision = flag;
    return this;
  }

  /**
   * @param flag