package main
import (
_ "github.com/lib/pq"
"github.com/xormplus/xorm"
"fmt"
"time"
"strconv"
)
//用戶表結(jié)構(gòu)
type User struct {
Id int `xorm:"not null pk autoincr INTEGER"`
Name string `xorm:"VARCHAR(20)"`
Created time.Time `xorm:"default 'now()' DATETIME"`
ClassId int `xorm:"default 1 INTEGER"`
}
//Class表結(jié)構(gòu)
type Class struct {
Id int `xorm:"not null pk autoincr INTEGER"`
Name string `xorm:"VARCHAR(20)"`
}
//臨時(shí)表結(jié)構(gòu)
type UserClass struct{
User `xorm:"extends"`
Name string
}
//此方法僅用于orm查詢時(shí)，查詢表認(rèn)定
func (UserClass) TableName() string {
return "public.user"
}
func main() {
//1.創(chuàng)建db引擎
db, err := xorm.NewPostgreSQL("postgres://postgres:123@localhost:5432/test?sslmode=disable")
if err != nil {
fmt.Println(err)
}
//2.顯示sql語(yǔ)句
db.ShowSQL(true)
//3.設(shè)置連接數(shù)
db.SetMaxIdleConns(2000)
db.SetMaxOpenConns(1000)
cacher := xorm.NewLRUCacher(xorm.NewMemoryStore(), 500)//緩存的條數(shù)
db.SetDefaultCacher(cacher)
//4.執(zhí)行插入語(yǔ)句的幾種方式
//4.1 orm插入方式:不好控制，如果僅僅插入的對(duì)象的屬性是name='ftq',那么其他的零值會(huì)一同insert，orm方式對(duì)零值的處理有點(diǎn)不太好
if false {
user := new(User)
user.Name = "ftq"
_, err = db.Insert(user)
if err != nil {
fmt.Println(err)
}
}
//4.2 命令插入方式
//4.2.1 db.Exec():單事務(wù)單次提交
if false{
sql:="insert into public.user(name) values(?)"
db.Exec(sql,"ft4")
}
//4.2.2 db.SQL().Execute():單事務(wù)準(zhǔn)備了Statement處理sql語(yǔ)句
if false{
sql:="insert into public.user(name) values(?)"
db.SQL(sql,"ft5").Execute()
}
//4.2.3使用sql配置文件管理語(yǔ)句,兩種載入配置的方式LoadSqlMap()和RegisterSqlMap(),以及SqlMapClient()替代SQL()
if false {
err = db.LoadSqlMap("./sql.xml")
//err = db.RegisterSqlMap(xorm.Xml("./","sql.xml"))
if err != nil {
fmt.Println(err)
}
db.SqlMapClient("insert_1","ft7").Execute()
}
//5.執(zhí)行查詢的幾種方式
//5.1 orm查詢:在user初始化的時(shí)候,該orm查詢直接通過掃描user類型確定表名;組合使用Where(),Get()
if false {
user := new(User)
boolget ,err2 :=db.Where("id=?",5).Get(user)
fmt.Println(boolget,err2,user)
}
//5.2 orm查詢:組合使用Where(),Get(),And()
if false {
user := new(User)
boolget ,err2 :=db.Where("id=?",5).And("name=?","ft7").And("id>?",3).Get(user)
fmt.Println(boolget,err2,user)
}
//5.3 orm查詢: AllCols()查詢所有列，Cols()查詢部分列，F(xiàn)ind()解析多行結(jié)果,Get()解析單行結(jié)果
if false {
users := new ([]User)
err = db.AllCols().Find(users)
//err = db.Cols("id","name").Find(users)
if err !=nil {
fmt.Println(err)
}
fmt.Println(users)
}
//5.4 orm查詢:連接查詢Join()
if false {
users := new([]UserClass)
db.Join("INNER","class","user.class_id=class.id").Find(users)
//db.SQL("select u.id,u.name,c.name from public.user as u left join public.class as c on u.class_id=c.id").Find(users)
fmt.Println(users)
}
//5.5 sql查詢略
if false {
//和insert類似,Find查找多行結(jié)果，Get獲取 單行結(jié)果
users := new([]UserClass)
db.SQL("select u.id,u.name,c.name from public.user as u left join public.class as c on u.class_id=c.id").Find(users)
fmt.Println(users)
}
//5.6 鏈?zhǔn)讲檎?
if false {
//值得一提的是，支持查找某行的某個(gè)字段，不過一般在sql語(yǔ)句中就可以完成過濾，如果sql語(yǔ)句過于復(fù)雜，可以鏈?zhǔn)讲檎疫^濾
id := db.SQL("select * from public.user").Query().Results[0]["id"]
fmt.Println(id)
}
//6.執(zhí)行更新
//6.1 ORM方式: 只有非0值的屬性會(huì)被更新，user的id和created都是默認(rèn)零值，不被處理
if false {
user :=new(User)
user.Name="ftx"
//[xorm] [info] 2018/02/08 12:04:01.330624 [SQL] UPDATE "user" SET "name" = $1 WHERE "id"=$2 []interface {}{"ftx", 4}
db.Id(4).Update(user)
}
//6.2 SQL方式略,和insert類似
//7.事務(wù)
//7.1簡(jiǎn)單事務(wù)
if false {
session :=db.NewSession()
defer session.Close()
session.Begin()
//業(yè)務(wù):新添加學(xué)生，并且創(chuàng)建新的班級(jí)，如果班級(jí)因?yàn)橹麈I沖突創(chuàng)建失敗，則整個(gè)事務(wù)回滾
_,err =session.SQL("insert into public.user(name,class_id) values('ft13',2)").Execute()
//表中已經(jīng)有id=3的班級(jí)了
_,err =session.SQL("insert into public.class(id,name) values(3,'高中3班')").Execute()
if err!=nil {
session.Rollback()
}
session.Commit()
}
//7.2嵌套事務(wù)
if false {
session := db.NewSession()
defer session.Close()
session.Begin()
_,err=session.Exec("insert into public.user(name,class_id) values('ft23',2)")
if err!=nil {
session.Rollback()
}
_,err=session.Exec("insert into public.user(id,name,class_id) values(1,'ft24',2)")
if err!=nil {
session.Rollback()
}
tx,_:=session.BeginTrans()
_,err=tx.Session().Exec("insert into public.user(name,class_id) values('ft25',2)")
if err!=nil {
tx.RollbackTrans()
}
tx.CommitTrans()
session.Commit()
}
//8.緩存:使用Raw方式修改以后，需要清理緩存
if true {
//建立500條數(shù)據(jù)
session := db.NewSession()
defer session.Close()
if false {
session.Begin()
for i := 30; i 530; i++ {
value := "ft" + strconv.Itoa(i)
_, err = session.Exec("insert into public.user(name) values(?)", value)
if err != nil {
session.Rollback()
}
}
session.Commit()
}
//查詢前531條數(shù)據(jù)，并隨意輸出其中一條
users := make([]User,10)
db.SQL("select * from public.user where id531 order by id").Find(users)
fmt.Println("讀第一遍:","id:",users[50].Id,"name:",users[50].Name)
db.SQL("select * from public.user where id531 order by id").Find(users)
fmt.Println("讀第二遍:","id:",users[50].Id,"name:",users[50].Name)
var step int =1
stepString := users[50].Name + strconv.Itoa(step)
session.Exec("update public.user set name=? where id =45",stepString)
//清理緩存
db.ClearCache(new(User))
time.Sleep(5*time.Second)
session.SQL("select * from public.user where id531 order by id").Find(users)
fmt.Println("讀第三遍:","id:",users[50].Id,"name:",users[50].Name)
//雖然很不好意思，但是就算開啟了緩存數(shù)據(jù)也是臟了
}
//9.讀寫分離
if false {
//假設(shè)有多臺(tái)服務(wù)器用來響應(yīng)客戶的讀請(qǐng)求
var dbGroup *xorm.EngineGroup
conns :=[]string {
"postgres://postgres:123@localhost:5432/test?sslmode=disable",
"postgres://postgres:123@localhost:5432/test?sslmode=disable",
"postgres://postgres:123@localhost:5432/test?sslmode=disable",
"postgres://postgres:123@localhost:5432/test?sslmode=disable",
}
//負(fù)載均衡策略:(特性自行百度)
// 1.xorm.RandomPolicy()隨機(jī)訪問負(fù)載均衡,
// 2.xorm.WeightRandomPolicy([]int{2, 3,4})權(quán)重隨機(jī)負(fù)載均衡
// 3.xorm.RoundRobinPolicy() 輪詢?cè)L問負(fù)載均衡
// 4.xorm.WeightRoundRobinPolicy([]int{2, 3,4}) 權(quán)重輪訓(xùn)負(fù)載均衡
// 5.xorm.LeastConnPolicy()最小連接數(shù)負(fù)載均衡
dbGroup, err = xorm.NewEngineGroup("postgres", conns, xorm.RoundRobinPolicy())
//dbGroup使用方法和db一致
//簡(jiǎn)單查詢
dbGroup.SQL("inser into public.users(name) values('ft2000')").Execute()
dbGroup.Exec("inser into public.users(name) values('ft2001')")
//事務(wù)查詢
session :=dbGroup.NewSession()
defer session.Close()
session.Begin()
_,err = session.Exec("inser into public.users(name) values('ft2001')")
if err!=nil {
session.Rollback()
}
session.Commit()
}
}
//注意:
//1.postgresql好像不會(huì)默認(rèn)按id增長(zhǎng)排序，所以書寫sql語(yǔ)句要提前寫好order by id ，樓主沒怎么寫，咳咳
//2. [5.4] postgresql建表會(huì)建在public策略的table里，所以查詢語(yǔ)句表明寫的是public.xxxx,這也造成了連表orm查詢會(huì)發(fā)生前綴報(bào)錯(cuò),比如變成了"SELECT * FROM "public"."user" INNER JOIN "class" ON user.class_id=class.id 這和內(nèi)部的split有關(guān)，
//3.[8.]帶的緩存好像很容易失效,在創(chuàng)建500個(gè)數(shù)據(jù)后，經(jīng)過查查改查的操作，查詢到的結(jié)果是一樣的始終是一樣的，本來改值之后應(yīng)該最后一遍查會(huì)變化，然而并沒有,緩存功能即使清理了緩存，還是會(huì)讀到臟的
