mysql_example
作者：互联网
package main
import (
"database/sql"
"fmt"
_ "github.com/go-sql-driver/mysql"
)
var DB *sql.DB
func initDb() error {
var err error
dsn := "root:root@tcp(localhost:3306)/golang_db"
DB, err = sql.Open("mysql", dsn)
if err != nil {
return err
}
DB.SetMaxOpenConns(100)
DB.SetMaxIdleConns(16)
return nil
}
type User struct {
Id int64 `db:"id"`
Name sql.NullString `db:"string"`
Age int `db:"age"`
}
func testQueryMultilRow() {
sqlstr := "select id, name, age from user where id > ?"
rows, err := DB.Query(sqlstr, 0)
//重点关注， rows对象一定要close掉
defer func() {
if rows != nil {
rows.Close()
}
}()
if err != nil {
fmt.Printf("query failed, err:%v\n", err)
return
}
for rows.Next() {
var user User
err := rows.Scan(&user.Id, &user.Name, &user.Age)
if err != nil {
fmt.Printf("scan failed, err:%v\n", err)
return
}
fmt.Printf("user:%#v\n", user)
}
}
func testQueryData() {
for i := 0; i < 101; i++ {
fmt.Printf("query %d times\n", i)
sqlstr := "select id, name, age from user where id=?"
row := DB.QueryRow(sqlstr, 2)
/*if row != nil {
continue
}*/
var user User
err := row.Scan(&user.Id, &user.Name, &user.Age)
if err != nil {
fmt.Printf("scan failed, err:%v\n", err)
return
}
fmt.Printf("id:%d name:%v age:%d\n", user.Id, user.Name, user.Age)
}
}
func testInsertData() {
sqlstr := "insert into user(name, age) values(?, ?)"
result, err := DB.Exec(sqlstr, "tom", 18)
if err != nil {
fmt.Printf("insert failed, err:%v\n", err)
return
}
id, err := result.LastInsertId()
if err != nil {
fmt.Printf("get last insert id failed, err:%v\n", err)
return
}
fmt.Printf("id is %d\n", id)
}
func testUpdateData() {
sqlstr := "update user set name=? where id=?"
result, err := DB.Exec(sqlstr, "jim", 3)
if err != nil {
fmt.Printf("insert failed, err:%v\n", err)
return
}
affected, err := result.RowsAffected()
if err != nil {
fmt.Printf("get affected rows failed, err:%v\n", err)
}
fmt.Printf("update db succ, affected rows:%d\n", affected)
}
func testDeleteData() {
sqlstr := "delete from user where id=?"
result, err := DB.Exec(sqlstr, 3)
if err != nil {
fmt.Printf("insert failed, err:%v\n", err)
return
}
affected, err := result.RowsAffected()
if err != nil {
fmt.Printf("get affected rows failed, err:%v\n", err)
}
fmt.Printf("delete db succ, affected rows:%d\n", affected)
}
func testPrepareData() {
sqlstr := "select id, name, age from user where id > ?"
stmt, err := DB.Prepare(sqlstr)
if err != nil {
fmt.Printf("prepare failed, err:%v\n", err)
return
}
defer func() {
if stmt != nil {
stmt.Close()
}
}()
rows, err := stmt.Query(0)
//重点关注， rows对象一定要close掉
defer func() {
if rows != nil {
rows.Close()
}
}()
if err != nil {
fmt.Printf("query failed, err:%v\n", err)
return
}
for rows.Next() {
var user User
err := rows.Scan(&user.Id, &user.Name, &user.Age)
if err != nil {
fmt.Printf("scan failed, err:%v\n", err)
return
}
fmt.Printf("user:%#v\n", user)
}
}
func testPrepareInsertData() {
sqlstr := "insert into user(name, age) values(?, ?)"
stmt, err := DB.Prepare(sqlstr)
if err != nil {
fmt.Printf("insert failed, err:%v\n", err)
return
}
defer func() {
if stmt != nil {
stmt.Close()
}
}()
result, err := stmt.Exec("jim", 100)
id, err := result.LastInsertId()
if err != nil {
fmt.Printf("get last insert id failed, err:%v\n", err)
return
}
fmt.Printf("id is %d\n", id)
}
func testTrans() {
conn, err := DB.Begin()
if err != nil {
if conn != nil {
conn.Rollback()
}
fmt.Printf("begin failed, err:%v\n", err)
return
}
sqlstr := "update user set age = 1 where id = ?"
_, err = conn.Exec(sqlstr, 1)
if err != nil {
conn.Rollback()
fmt.Printf("exec sql:%s failed, err:%v\n", sqlstr, err)
return
}
sqlstr = "update user set age = 2 where id = ?"
_, err = conn.Exec(sqlstr, 2)
if err != nil {
conn.Rollback()
fmt.Printf("exec second sql:%s failed, err:%v\n", sqlstr, err)
return
}
err = conn.Commit()
if err != nil {
fmt.Printf("commit failed, err:%v\n", err)
conn.Rollback()
return
}
}
func main() {
err := initDb()
if err != nil {
fmt.Printf("init db failed, err:%v\n", err)
return
}
//testQueryData()
//testQueryMultilRow()
//testInsertData()
//testUpdateData()
//testDeleteData()
//testPrepareData()
//testPrepareInsertData()
testTrans()
}
package main
import (
"database/sql"
"fmt"
_ "github.com/go-sql-driver/mysql"
"github.com/jmoiron/sqlx"
)
var DB *sqlx.DB
func initDb() error {
var err error
dsn := "root:root@tcp(localhost:3306)/golang_db"
DB, err = sqlx.Open("mysql", dsn)
if err != nil {
return err
}
DB.SetMaxOpenConns(100)
DB.SetMaxIdleConns(16)
return nil
}
type User struct {
Id int64 `db:"id"`
Name sql.NullString `db:"name"`
Age int `db:"age"`
}
func testQuery() {
sqlstr := "select id, name, age from user where id=?"
var user User
err := DB.Get(&user, sqlstr, 2)
if err != nil {
fmt.Printf("get failed, err:%v\n", err)
return
}
fmt.Printf("user:%#v\n", user)
}
func testQueryMulti() {
sqlstr := "select id, name, age from user where id>?"
var user []User
err := DB.Select(&user, sqlstr, 1)
if err != nil {
fmt.Printf("get failed, err:%v\n", err)
return
}
fmt.Printf("user:%#v\n", user)
}
func testUpdate() {
sqlstr := "update user set name=? where id=?"
result, err := DB.Exec(sqlstr, "abc", 1)
if err != nil {
fmt.Printf("update failed, err:%v\n", err)
return
}
count, err := result.RowsAffected()
if err != nil {
fmt.Printf("affected rows failed, err:%v\n", err)
return
}
fmt.Printf("affect rows:%d\n", count)
}
func queryDB(name string) {
sqlstr := fmt.Sprintf("select id, name, age from user where name='%s'", name)
fmt.Printf("sql:%s\n", sqlstr)
var user []User
err := DB.Select(&user, sqlstr)
if err != nil {
fmt.Printf("select failed, err:%v\n", err)
return
}
for _, v := range user {
fmt.Printf("user:%#v\n", v)
}
}
func queryDBBySqlx(name string) {
sqlstr := "select id, name, age from user where name=?"
//fmt.Printf("sql:%s\n", sqlstr)
var user []User
err := DB.Select(&user, sqlstr, name)
if err != nil {
fmt.Printf("select failed, err:%v\n", err)
return
}
for _, v := range user {
fmt.Printf("user:%#v\n", v)
}
}
func testSqlInject() {
//queryDB("abc' or 1 = 1 #")
//queryDB("name=abc' and (select count(*) from user ) < 10#")
//queryDB("name=123' union select *from user #")
queryDBBySqlx("name=123' union select *from user #")
}
func main() {
err := initDb()
if err != nil {
fmt.Printf("init db failed, err:%v\n", err)
return
}
//testQuery()
//testQueryMulti()
//testUpdate()
testSqlInject()
}
标签：nil,err,fmt,mysql,user,Printf,example,sqlstr 来源： https://www.cnblogs.com/sunlong88/p/11723178.html