model define

go.mod

@@ -4,6 +4,7 @@ go 1.20
 
 require (
 	github.com/go-sql-driver/mysql v1.7.0 // indirect
+	github.com/google/uuid v1.3.0 // indirect
 	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/jinzhu/now v1.1.5 // indirect
 	gorm.io/driver/mysql v1.4.7 // indirect

go.sum

@@ -1,5 +1,7 @@
 github.com/go-sql-driver/mysql v1.7.0 h1:ueSltNNllEqE3qcWBTD0iQd3IpL/6U+mJxLkazJ7YPc=
 github.com/go-sql-driver/mysql v1.7.0/go.mod h1:OXbVy3sEdcQ2Doequ6Z5BW6fXNQTmx+9S1MCJN5yJMI=
+github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
+github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/jinzhu/inflection v1.0.0 h1:K317FqzuhWc8YvSVlFMCCUb36O/S9MCKRDI7QkRKD/E=
 github.com/jinzhu/inflection v1.0.0/go.mod h1:h+uFLlag+Qp1Va5pdKtLDYj+kHp5pxUVkryuEj+Srlc=
 github.com/jinzhu/now v1.1.4/go.mod h1:d3SSVoowX0Lcu0IBviAWJpolVfI5UJVZZ7cO71lE/z8=

init.go

@@ -66,4 +66,6 @@ func init() {
 	}
 
 	DB = db
+	// 注册序列化器
+	schema.RegisterSerializer("csv", CSVSerializer{})
 }

model.go

@@ -1,9 +1,15 @@
 package gormExample
 
 import (
+	"context"
+	"database/sql"
 	"fmt"
+	"github.com/google/uuid"
 	"gorm.io/gorm"
+	"gorm.io/gorm/schema"
 	"log"
+	"reflect"
+	"strings"
 	"time"
 )
 
@@ -36,7 +42,7 @@ type TypeMap struct {
 }
 
 func Migrate() {
-	if err := DB.Debug().AutoMigrate(&TypeMap{}, &Post{}, &Category{}, &PostCategory{}, &Box{}); err != nil {
+	if err := DB.Debug().AutoMigrate(&Service{}, &IAndC{}, &FieldTag{}, &TypeMap{}, &Post{}, &Category{}, &PostCategory{}, &Box{}); err != nil {
 		log.Fatal(err)
 	}
 }
@@ -52,3 +58,224 @@ func PointerDiff() {
 	DB.First(typeMap, 1)
 	fmt.Printf("%+v\n", typeMap)
 }
+
+type CustomTypeModel struct {
+	gorm.Model
+
+	FTime     time.Time
+	FNullTime sql.NullTime
+
+	FString     string
+	FNullString sql.NullString
+
+	FUUID     uuid.UUID
+	FNullUUID uuid.NullUUID
+}
+
+func CustomType() {
+	//id := uuid.UUID{}
+	//id.Scan()  // Scanner
+	//id.Value() // Valuer
+
+	// 初始化模型
+	ctm := &CustomTypeModel{}
+	// 迁移数据表
+	DB.AutoMigrate(ctm)
+
+	// 创建
+	ctm.FTime = time.Now()         // 当前时间
+	ctm.FNullTime = sql.NullTime{} // 零值，Valid默认为false
+	ctm.FString = ""
+	ctm.FNullString = sql.NullString{}
+
+	ctm.FUUID = uuid.New()
+	ctm.FNullUUID = uuid.NullUUID{}
+
+	DB.Create(ctm)
+
+	// 查询
+	DB.First(ctm, ctm.ID)
+
+	// 判定字段是否为NULL
+	if ctm.FString == "" {
+		fmt.Println("FString is NULL")
+	} else {
+		fmt.Println("FString is NOT NULL")
+	}
+
+	if ctm.FNullString.Valid == false {
+		fmt.Println("FNullString is NULL")
+	} else {
+		fmt.Println("FNullString is NOT NULL")
+	}
+}
+
+type FieldTag struct {
+	//Field string `gorm:"" json:"" bson:"" xml:""` // Tag
+	gorm.Model
+
+	// string 类型的处理
+	FStringDefault string `gorm:""`
+	FTypeChar      string `gorm:"type:char(32)"`
+	FTypeVarchar   string `gorm:"type:varchar(255)"`
+	FTypeText      string `gorm:"type:text"`
+	FTypeBlob      []byte `gorm:"type:blob"`
+	FTypeEnum      string `gorm:"type:enum('Go', 'GORM', 'MySQL')"`
+	FTypeSet       string `gorm:"type:set('Go', 'GORM', 'MySQL')"`
+
+	FColNum string `gorm:"column:custom_column_name"`
+	// 默认是NULl
+	FColNotNull string `gorm:"type:varchar(255);not null;"`
+	FColDefault string `gorm:"type:varchar(255);not null;default:gorm middle ware;"`
+	FColComment string `gorm:"type:varchar(255);comment:带有注释的字段"`
+}
+
+type IAndC struct {
+	// 基础索引类型
+	ID    uint   `gorm:"primaryKey"`
+	Email string `gorm:"type:varchar(255);uniqueIndex"` // unique
+	Age   uint8  `gorm:"index;check:age >= 18 AND email is not null"`
+
+	// 复合索引
+	FirstName string `gorm:"index:name"`
+	LastName  string `gorm:"index:name"`
+	// 顺序关键顺序
+	// 默认的 priority:10
+	FirstName1 string `gorm:"index:name1,priority:2"`
+	LastName1  string `gorm:"index:name1,priority:1"`
+
+	// 索引选项，前缀长度，排序方式，comment
+	Height      float32 `gorm:"index:,sort:desc"`
+	AddressHash string  `gorm:"index:,length:12,comment:前12个字符作为索引关键字"`
+}
+
+func IAndCCreate() {
+	iac := &IAndC{}
+	iac.Age = 18
+	if err := DB.Create(iac).Error; err != nil {
+		log.Fatal(err)
+	}
+	fmt.Printf("%+v\n", iac)
+}
+
+type Service struct {
+	gorm.Model
+
+	//Url         string `gorm:"-"` // -:all
+	Url         string `gorm:"-:migration; type:varchar(255)"`
+	Schema      string
+	Host        string `gorm:"<-:false"`
+	Path        string `gorm:"<-:update"`
+	QueryString string `gorm:"->:false"`
+}
+
+func ServiceCRUD() {
+	s := &Service{}
+	s.Schema = "http"
+	s.Host = "www.mashibing.com"
+	s.Path = "/"
+	s.Url = "http://www.mashibing.com/"
+	DB.Create(s)
+}
+
+func PaperCrud() {
+	if err := DB.AutoMigrate(&Paper{}); err != nil {
+		log.Fatal(err)
+	}
+
+	// 常规操作
+	paper := &Paper{}
+	paper.Subject = "使用Serializer操作Tags字段"
+	paper.Tags = []string{"Go", "Serializer", "Gorm", "MySQL"}
+	// create 会执行序列化工作,serialize
+	if err := DB.Create(paper).Error; err != nil {
+		log.Fatal(err)
+	}
+
+	// 查询
+	newPaper := &Paper{}
+	// First会执行反序列化工作，unserialize
+	DB.First(newPaper, 5)
+	fmt.Printf("%+v\n", newPaper)
+
+}
+
+// 1.定义实现了序列化器接口的类型
+type CSVSerializer struct{}
+
+// 实现Scan，unserialize时执行
+// ctx Context对象
+// field 模型的字段对应的类型
+// dst 目标值（最终结果赋值到dst）
+// dbValue 从数据库读取的值
+// 错误
+func (CSVSerializer) Scan(ctx context.Context, field *schema.Field, dst reflect.Value, dbValue interface{}) error {
+	// 初始化一个用来存储字段值的变量
+	var fieldValue []string
+	// 一:解析读取到的数据表的数据
+	if dbValue != nil { // 不是 NULL
+		// 支持解析的只有string和[]byte
+		// 使用类型检测进行判定
+		var str string
+		switch v := dbValue.(type) {
+		case string:
+			str = v
+		case []byte:
+			str = string(v)
+		default:
+			return fmt.Errorf("failed to unmarshal CSV value: %#v", dbValue)
+		}
+		// 二：核心：将数据表中的字段使用逗号分割，形成 []string
+		fieldValue = strings.Split(str, ",")
+	}
+
+	// 三，将处理好的数据，设置到dst上
+	field.ReflectValueOf(ctx, dst).Set(reflect.ValueOf(fieldValue))
+	return nil
+}
+
+// 实现Value, serialize时执行
+// fieldValue 模型的的字段值
+func (CSVSerializer) Value(ctx context.Context, field *schema.Field, dst reflect.Value, fieldValue interface{}) (interface{}, error) {
+	// 将字段值转换为可存储的CSV结构
+	return strings.Join(fieldValue.([]string), ","), nil
+}
+
+type Paper struct {
+	gorm.Model
+
+	Subject string
+	//Tags    []string
+	// 使用 json 序列化器进行处理
+	Tags []string `gorm:"serializer:json"`
+	// 使用自定义的编码器
+	Categories []string `gorm:"serializer:csv"`
+}
+
+// 2.注册到GORM中
+// 3.测试
+func CustomSerializer() {
+	// 注册序列化器
+	schema.RegisterSerializer("csv", CSVSerializer{})
+
+	// 测试
+	if err := DB.AutoMigrate(&Paper{}); err != nil {
+		log.Fatal(err)
+	}
+
+	// 常规操作
+	paper := &Paper{}
+	paper.Subject = "使用自定义的Serializer操作Categories字段"
+	paper.Tags = []string{"Go", "Serializer", "Gorm", "MySQL"}
+	paper.Categories = []string{"Go", "Serializer", "Gorm", "MySQL"}
+	// create 会执行序列化工作,serialize
+	if err := DB.Create(paper).Error; err != nil {
+		log.Fatal(err)
+	}
+
+	// 查询
+	newPaper := &Paper{}
+	// First会执行反序列化工作，unserialize
+	DB.First(newPaper, paper.ID)
+	fmt.Printf("%+v\n", newPaper)
+}

model_test.go

@@ -9,3 +9,23 @@ func TestMigrate(t *testing.T) {
 func TestPointerDiff(t *testing.T) {
 	PointerDiff()
 }
+
+func TestCustomType(t *testing.T) {
+	CustomType()
+}
+
+func TestIAndCCreate(t *testing.T) {
+	IAndCCreate()
+}
+
+func TestServiceCRUD(t *testing.T) {
+	ServiceCRUD()
+}
+
+func TestPaperCrud(t *testing.T) {
+	PaperCrud()
+}
+
+func TestCustomSerializer(t *testing.T) {
+	CustomSerializer()
+}