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Go sql.Driver的mysql Driver 中的一个有意思的行为

 2 years ago
source link: https://www.imhanjm.com/2018/11/29/go%20sql.driver%E7%9A%84mysql%20driver%20%E4%B8%AD%E7%9A%84%E4%B8%80%E4%B8%AA%E6%9C%89%E6%84%8F%E6%80%9D%E7%9A%84%E8%A1%8C%E4%B8%BA/
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Go sql.Driver的mysql Driver 中的一个有意思的行为

发表于 2018-11-29

| 0 Comments

如果参数中没有参数, 则直接query.
如果sql中有参数, 且打开了InterpolateParams开关, 那么就客户端直接拼参数到SQL里, 不需要prepare直接query.
如果sql中有参数, 且没有打开InterpolateParams(默认设置), 且带参数, 就会走先prepare再发query参数两步.

github.com/go-sql-driver/mysql/connection.go:370
func (mc *mysqlConn) query(query string, args []driver.Value) (*textRows, error) {
//...
if len(args) != 0 {
	if !mc.cfg.InterpolateParams {
		return nil, driver.ErrSkip
	}
	// try client-side prepare to reduce roundtrip
	prepared, err := mc.interpolateParams(query, args)
	if err != nil {
		return nil, err
	}
	query = prepared
}
// Send command
err := mc.writeCommandPacketStr(comQuery, query)
if err == nil {
	// Read Result
// ...

后续再补篇文章详细写写sql.Driver


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