model.go

package orm

import (
	"database/sql/driver"
	"encoding/json"
	"time"
)

// Index 索引信息
type Index map[string]interface{}

// ArgTrans 开启事务的参数
type ArgTrans struct {
	Level   string        // 事务级别
	Timeout time.Duration // 超时回滚
}

// ArgObjects 获取Objects的定制参数
type ArgObjects struct {
	LogLevel int // 日志级别
}

// Model 模型定义
type Model interface {
	String() string                      // 表名
	Objects() Objects                    // 返回object对象
	ObjectsWith(opt *ArgObjects) Objects // 返回object对象

	// 通过tag来定义索引:
	// unique索引    Name string `sorm:"unique"`
	// index索引     Name string `sorm:"index"`
	// TODO: 全文索引 Name string `sorm:"text"`
	Ensure(st interface{}) error // 通过struct的tag来 添加字段,确认索引
	// 确认字段存在
	EnsureColumn(st interface{}) error
	// 确认索引存在
	EnsureIndex(index Index) error

	// 事务
	Begin() (Trans, error)                  // 事务开始
	BeginWith(opt *ArgTrans) (Trans, error) // 指定事务开始
	Commit(Trans) error                     // 阶段二提交
	Rollback(Trans) error                   // 回滚操作
	AutoTrans(Trans) error                  // 依据Trans内是否储存有错误来自动决定回滚或提交

	// 表的读写锁
	Lock()
	Unlock()
	RLock()
	RUnlock()

	// 直接执行数据库语句
	Exec(query string, args ...interface{}) (result Result, err error)
	Select(dest interface{}, query string, args ...interface{}) (err error)
	// 删表
	Drop() error

	// other
	With(opt *ArgModel) Model // 返回一个新的model
}

// Result summarizes an executed SQL command. 结果信息
type Result interface {
	// LastInsertId returns the integer generated by the database
	// in response to a command. Typically this will be from an
	// "auto increment" column when inserting a new row. Not all
	// databases support this feature, and the syntax of such
	// statements varies.
	LastInsertId() (int64, error)

	// RowsAffected returns the number of rows affected by an
	// update, insert, or delete. Not every database or database
	// driver may support this.
	RowsAffected() (int64, error)
}

// TypeJSONValue 通用json内联字段
type TypeJSONValue struct{}

// Value SQL规范
func (m TypeJSONValue) Value() (driver.Value, error) {
	return json.Marshal(m)
}

// Scan SQL规范
func (m *TypeJSONValue) Scan(src interface{}) (err error) {
	return json.Unmarshal(src.([]byte), m)
}