golang连接不同数据库的方式参数有不同
我这里的案例是，创建一个产品表
方案1方案2
测试案例
1、database/sql
需要下载第三方库，go get github.com/bmizerany/pq
package main
import (
"database/sql" //通用的接口
"fmt"
_ "github.com/bmizerany/pq" //必须要有相应的驱动
)
/**
* @author Lenovo
* @date 2020/9/16
*/
const (
host = "localhost"
port = 5432
user = "postgres"
password = "" //你自己数据库的密码
dbname = "test" //创建的数据库
)
var db *sql.DB // 连接池对象
var err error
type product struct {
ProductNo string
Name string
Price float64
}
type productDao struct{}
func main() {
pd := new(productDao)
err = pd.initDB()
if err != nil {
fmt.Println("initDB() failed. ")
}
defer pd.closeDB()
pd.doQueryAll()
pd.doPreQueryByName("apple")
}
func (pd *productDao) initDB() (err error) {
pdqlInfo := fmt.Sprintf("host=%s port=%d user=%s "+
"password=%s dbname=%s sslmode=disable",
host, port, user, password, dbname)
// pdqlInfo := "postgres:密码@tcp(127.0.0.1:5432)/test" // 用户名:密码@tcp(ip端口)/数据库名字，暂时出错
db, err = sql.Open("postgres", pdqlInfo) //Open(driverName 驱动名字, dataSourceName string 数据库信息)
// DB 代表一个具有零到多个底层连接的连接池，可以安全的被多个go程序同时使用
//这里的open函数只是验证参数是否合法，而不会创建和数据库的连接,也不会检查账号密码是否正确
if err != nil {
fmt.Println("Wrong args.Connected failed.")
return err
}
err = db.Ping()
if err != nil {
fmt.Println("Connected failed.")
return err
}
db.SetMaxOpenConns(20) //设置数据库连接池最大连接数
db.SetMaxIdleConns(10) //设置最大空闲连接数
fmt.Println("Successfully connected!")
return nil
}
func (pd *productDao) closeDB() (err error) {
return db.Close()
}
func (pd *productDao) doQueryAll() (error, []product) {
rows, err := db.Query(`Select * from products`)
if err != nil {
fmt.Println("Some amazing wrong happens in the process of Query.", err)
return err, []product{}
}
products := make([]product, 0)
defer rows.Close() //关闭连接
index := 0
var p product
for rows.Next() {
err := rows.Scan(&p.ProductNo, &p.Name, &p.Price)
products = append(products, p)
if err != nil { // 获得的都是字符串
fmt.Println("Some amazing wrong happens in the process of queryAll.", err)
return err, products
}
index++
}
if index > 0 {
fmt.Println("The data of table is as follow.")
for _, p := range products {
fmt.Printf("%v %s %v\n", p.ProductNo, p.Name, p.Price)
}
fmt.Println("Successfully query ", len(products))
return nil, products
} else {
fmt.Println("No such data exists in database. ")
return fmt.Errorf("No such data exists in database. "), products
}
}
func (pd *productDao) doQueryByPrice(price float32) (error, []product) {
rows, err := db.Query(`Select * from products where price=$1`, price)
if err != nil {
fmt.Println("Some amazing wrong happens in the process of Query.", err)
return err, []product{}
}
products := make([]product, 0)
defer rows.Close() //关闭连接
index := 0
var p product
for rows.Next() {
err := rows.Scan(&p.ProductNo, &p.Name, &p.Price)
products = append(products, p)
if err != nil { // 获得的都是字符串
fmt.Println("Some amazing wrong happens in the process of queryAll.", err)
return err, products
}
index++
}
if index > 0 {
fmt.Println("The data of table is as follow.")
for _, p := range products {
fmt.Printf("%v %s %v\n", p.ProductNo, p.Name, p.Price)
}
fmt.Println("Successfully query ", len(products))
return nil, products
} else {
fmt.Println("No such data exists in database. ")
return fmt.Errorf("No such data exists in database. "), products
}
}
func (pd *productDao) doQueryByName(pname string) (error, []product) {
rows, err := db.Query(`Select * from products where name=$1`, pname)
if err != nil {
fmt.Println("Some amazing wrong happens in the process of Query.", err)
return err, []product{}
}
products := make([]product, 0)
defer rows.Close() //关闭连接
index := 0
var p product
for rows.Next() {
err := rows.Scan(&p.ProductNo, &p.Name, &p.Price)
products = append(products, p)
if err != nil { // 获得的都是字符串
fmt.Println("Some amazing wrong happens in the process of queryAll.", err)
return err, products
}
index++
}
if index > 0 {
fmt.Println("The data of table is as follow.")
for _, p := range products {
fmt.Printf("%v %s %v\n", p.ProductNo, p.Name, p.Price)
}
fmt.Println("Successfully query ", len(products))
return nil, products
} else {
fmt.Println("No such data exists in database. ")
return fmt.Errorf("No data exists in database. "), products
}
}
func (pd *productDao) doPreQueryByName(pname string) (error, []product) {
sqlStr := "Select * from products where name=$1"
stmt, err := db.Prepare(sqlStr)
if err != nil {
fmt.Printf("prepare failed, err:%v\n", err)
return err, []product{}
}
defer stmt.Close()
rows, err := stmt.Query(pname)
if err != nil {
fmt.Printf("query failed, err:%v\n", err)
return err, []product{}
}
defer rows.Close()
index := 0
products := make([]product, 0)
var p product
// 循环读取结果集中的数据
for rows.Next() {
err := rows.Scan(&p.ProductNo, &p.Name, &p.Price)
products = append(products, p)
if err != nil { // 获得的都是字符串
fmt.Println("Some amazing wrong happens in the process of queryAll.", err)
return err, []product{}
}
index++
}
if index > 0 {
fmt.Println("The data of table is as follow.")
for _, p := range products {
fmt.Printf("%v %s %v\n", p.ProductNo, p.Name, p.Price)
}
fmt.Println("Successfully query ", len(products))
return nil, products
} else {
fmt.Println("No such data exists in database. ")
return fmt.Errorf("No data exists in database. "), products
}
}
func (pd *productDao) doQueryByNo(pno string) (error, product) {
var p product
// 1、写查询单条记录的sql语句
sqlStr := "Select * from products where ProductNo = $1"
// 2、执行
row := db.QueryRow(sqlStr, pno)
// 3、获得结果
err = row.Scan(&p.ProductNo, &p.Name, &p.Price)
if err != nil {
fmt.Println("Some amazing wrong happens in the process of queryByNo :", err)
return err, product{}
}
fmt.Printf("%v %s %v\n", p.ProductNo, p.Name, p.Price)
fmt.Println("Successfully query 1")
return nil, p
}
func (pd *productDao) doInsertMulti(projects []product) error {
stmt, err := db.Prepare("Insert into products(Product_No,Name,Price) values($1,$2,$3)")
if err != nil {
fmt.Println("Some amazing wrong happens in preparation for the insert.")
return err
}
defer stmt.Close()
for i, project := range projects {
_, err := stmt.Exec(project.ProductNo, project.Name, project.Price)
if err != nil {
fmt.Println("Some amazing wrong happens in the process of doInsertMulti.")
fmt.Println("But successfully insert ", i)
return err
}
}
fmt.Println("Successfully add", len(projects))
return nil
}
func (pd *productDao) doInsertOne(project product) error {
stmt, err := db.Prepare("Insert into products(Product_No,Name,Price) values($1,$2,$3)")
if err != nil {
fmt.Println("Some amazing wrong happens in preparation for the insert.")
//log.Fatal(err)
return err
}
defer stmt.Close()
res, err := stmt.Exec(project.ProductNo, project.Name, project.Price)
if err != nil {
fmt.Println("Some amazing wrong happens in the process of doInsertOne.")
//log.Fatal(err)
return err
}
num, err := res.RowsAffected()
if err != nil {
fmt.Println("Some amazing wrong happens in the affected fo deletion.")
return err
}
fmt.Println("Successfully add ", num)
return nil
}
func (pd *productDao) doDeleteByNo(pno string) error {
stmt, err := db.Prepare(`Delete FROM products where productno = $1`)
if err != nil {
fmt.Println("Some amazing wrong happens in preparation for the deletion.")
return err
}
res, err := stmt.Exec(pno)
if err != nil {
fmt.Println("Some amazing wrong happens in execution for the deletion.")
return err
}
num, err := res.RowsAffected()
if err != nil {
fmt.Println("Some amazing wrong happens in the affected fo deletion.")
return err
}
fmt.Println("Successfully delete", num)
return nil
}
func (pd *productDao) doDeleteByName(pname string) error {
stmt, err := db.Prepare(`Delete FROM products where name = $1`)
if err != nil {
fmt.Println("Some amazing wrong happens in preparation for the deletion.")
return err
}
res, err := stmt.Exec(pname)
if err != nil {
fmt.Println("Some amazing wrong happens in execution for the deletion.")
return err
}
num, err := res.RowsAffected()
if err != nil {
fmt.Println("Some amazing wrong happens in the affected fo deletion.")
return err
}
fmt.Println("Successfully delete", num)
return nil
}
func (pd *productDao) doUpdatePriceByNo(pno string, newValue float32) error {
stmt, err := db.Prepare("Update products set price = $2 where product_no = $1")
if err != nil {
fmt.Println("Some amazing wrong happens in preparation for the update.")
//log.Fatal(err)
return err
}
defer stmt.Close()
res, err := stmt.Exec(pno, newValue)
if err != nil {
fmt.Println("Some amazing wrong happens in execution for the update.")
return err
}
num, err := res.RowsAffected()
if err != nil {
fmt.Println("Some amazing wrong happens in the affected fo update.")
return err
}
fmt.Println("Successfully update ", num)
return nil
}
func (pd *productDao) doUpdatePriceByName(pname string, newValue float32) error {
stmt, err := db.Prepare("Update products set price = $2 where name = $1")
if err != nil {
fmt.Println("Some amazing wrong happens in preparation for the update.")
//log.Fatal(err)
return err
}
defer stmt.Close()
res, err := stmt.Exec(pname, newValue)
if err != nil {
fmt.Println("Some amazing wrong happens in execution for the update.")
//log.Fatal(err)
return err
}
num, err := res.RowsAffected()
if err != nil {
fmt.Println("Some amazing wrong happens in the affected fo update.")
return err
}
fmt.Println("Successfully update ", num)
return nil
}
2、扩展的sqlx
需要下载github.com/jmoiron/sqlx
sqlx可以认为是Go语言内置database/sql的超集，它在优秀的内置database/sql基础上提供了一组扩展。这些扩展中除了大家常用来查询的Get(dest interface{}, …) error和Select(dest interface{}, …) error外还有很多其他强大的功能。
package main
import (
"fmt"
_ "github.com/bmizerany/pq" //必须要有相应的驱动
"github.com/jmoiron/sqlx"
)
/**
* @author Lenovo
* @date 2020/9/21
*/
const (
host = "localhost"
port = 5432
user = "postgres"
password = "" //你自己数据库的密码
dbname = "test" //创建的数据库
)
var db *sqlx.DB // 连接池对象
var err error
type productDao struct{}
type product struct {
ProductNo string
Name string
Price float64
}
func main() {
pd := new(productDao)
pd.initDB()
defer pd.closeDB()
pd.doQueryAll()
pd.doUpdatePriceByName("eraser",58.99)
pd.doQueryByNo("5")
pd.doQueryByName("eraser")
}
func (pd *productDao) initDB() (err error) {
pdqlInfo := fmt.Sprintf("host=%s port=%d user=%s "+
"password=%s dbname=%s sslmode=disable",
host, port, user, password, dbname)
db, err = sqlx.Connect("postgres", pdqlInfo)
if err != nil {
fmt.Printf("Connected failed.err:%v\n", err)
return err
}
db.SetMaxOpenConns(20)
db.SetMaxIdleConns(10)
fmt.Println("Successfully connected!")
return nil
}
func (pd *productDao) closeDB() (err error) {
return db.Close()
}
func (pd *productDao) doQueryAll() (error, []product) {
sqlStr := "Select * from products"
var products []product
err := db.Select(&products, sqlStr)
if err != nil {
fmt.Println("Some amazing wrong happens in the process of queryAll.err:", err)
return err, products
}
for _, p := range products {
fmt.Printf("%v %s %v\n", p.ProductNo, p.Name, p.Price)
}
fmt.Println("Successfully query ", len(products))
return nil, products
}
func (pd *productDao) doQueryByPrice(price float32) (error, []product) {
sqlStr := "Select * from products where price=$1"
var products []product
err := db.Select(&products, sqlStr, price)
if err != nil {
fmt.Println("Some amazing wrong happens in the process of queryByPrice.err:", err)
return err, products
}
for _, p := range products {
fmt.Printf("%v %s %v\n", p.ProductNo, p.Name, p.Price)
}
fmt.Println("Successfully query ", len(products))
return nil, products
}
func (pd *productDao) doQueryByName(pname string) (error, []product) {
sqlStr := "Select * from products where name=$1"
var products []product
err := db.Select(&products, sqlStr, pname)
if err != nil {
fmt.Println("Some amazing wrong happens in the process of queryByName.err:", err)
return err, products
}
for _, p := range products {
fmt.Printf("%v %s %v\n", p.ProductNo, p.Name, p.Price)
}
fmt.Println("Successfully query ", len(products))
return nil, products
}
func (pd *productDao) doQueryByNo(pno string) (error, product) {
var p product
sqlStr := "Select * from products where productno = $1"
err := db.Get(&p, sqlStr, pno)
if err != nil {
fmt.Println("Some amazing wrong happens in the process of queryByName.err:", err)
return err, p
}
fmt.Printf("%s %s %v\n", p.ProductNo, p.Name, p.Price)
fmt.Println("Successfully query 1")
return nil, p
}
func (pd *productDao) doInsertOne(project product) error {
sqlStr := "Insert into products(ProductNo,Name,Price) values($1,$2,$3)"
res, err := db.Exec(sqlStr, project.ProductNo, project.Name, project.Price)
if err != nil {
fmt.Printf("Some amazing wrong happens in the process of doInsertOne.err:%v\n", err)
return err
}
num, err := res.RowsAffected()
if err != nil {
fmt.Println("Some amazing wrong happens in the affected fo deletion.")
return err
}
fmt.Println("Successfully insert ", num)
return nil
}
func (pd *productDao) doInsertMulti(projects []product) error {
sqlStr := "Insert into products(ProductNo,Name,Price) values($1,$2,$3)"
for i, project := range projects {
_, err = db.Exec(sqlStr, project.ProductNo, project.Name, project.Price)
if err != nil {
fmt.Printf("Some amazing wrong happens in the process of doInsertMulti.err:%v\n", err)
fmt.Println("But successfully insert ", i)
return err
}
}
if err != nil {
fmt.Println("Some amazing wrong happens in the affected fo deletion.")
return err
}
fmt.Println("Successfully insert ", len(projects))
return nil
}
func (pd *productDao) doUpdatePriceByNo(pno string, newValue float32) error {
sqlStr := "Update products set price = $2 where productno = $1"
ret, err := db.Exec(sqlStr, pno, newValue)
if err != nil {
fmt.Printf("update failed, err:%v\n", err)
return err
}
n, err := ret.RowsAffected() // 操作影响的行数
if err != nil {
fmt.Printf("get RowsAffected failed, err:%v\n", err)
return err
}
fmt.Printf("update success, affected rows:%d\n", n)
return nil
}
func (pd *productDao) doUpdatePriceByName(pname string, newValue float32) error {
sqlStr := "Update products set price = $2 where name = $1"
ret, err := db.Exec(sqlStr, pname, newValue)
if err != nil {
fmt.Printf("update failed, err:%v\n", err)
return err
}
n, err := ret.RowsAffected() // 操作影响的行数
if err != nil {
fmt.Printf("get RowsAffected failed, err:%v\n", err)
return err
}
fmt.Printf("update success, affected rows:%d\n", n)
return nil
}
// 删除数据
func (pd *productDao) doDeleteByNo(pno string) error {
sqlStr := "delete from products where productno = $1"
ret, err := db.Exec(sqlStr, pno)
if err != nil {
fmt.Printf("delete failed, err:%v\n", err)
return err
}
n, err := ret.RowsAffected() // 操作影响的行数
if err != nil {
fmt.Printf("get RowsAffected failed, err:%v\n", err)
return err
}
fmt.Printf("delete success, affected rows:%d\n", n)
return nil
}
func (pd *productDao) doDeleteByName(pname string) error {
sqlStr := "Delete FROM products where name = $1"
ret, err := db.Exec(sqlStr, pname)
if err != nil {
fmt.Printf("delete failed, err:%v\n", err)
return err
}
n, err := ret.RowsAffected() // 操作影响的行数
if err != nil {
fmt.Printf("get RowsAffected failed, err:%v\n", err)
return err
}
fmt.Printf("delete success, affected rows:%d\n", n)
return nil
}
package model
import (
"fmt"
"testing"
)
//TestMain函数可以在测试函数执行之前做一些其他操作
func TestMain(m *testing.M) {
fmt.Println("测试开始：")
m.Run()
}
func TestProduct(t *testing.T) {
fmt.Println("开始测试相关方法")
//通过t.Run()来执行子测试函数
t.Run("查看商品:", testDoQueryAll)
}
func testDoQueryAll(t *testing.T){
pd := new(productDao)
pd.initDB()
defer pd.closeDB()
pd.doQueryAll()
}
回到方案1、方案2
