資料庫無關的GO語言ORM - hood

這是一個建立於 的文章，其中的資訊可能已經有所發展或是發生改變。

項目地址：https://github.com/eaigner/hood

這是一個極具美感的ORM庫。

特性

• 鏈式的api
  
• 事務支援
  
• 遷移和名字空間產生
  
• 模型變數
  
• 模型時間
  
• 資料庫方言介面
  
• 沒有含糊的欄位
  
• 乾淨可測試的代碼

開啟資料庫

如果方言已經註冊可以直接開啟資料庫

hd, err := hood.Open("postgres", "user= dbname=")

你也可以開啟資料庫時候指定方言

hd := hood.New(db, NewPostgres())

Schemas

你可以這樣聲明

type Person struct {  // Auto-incrementing int field 'id'  Id hood.Id   // Custom primary key field 'first_name', with presence validation  FirstName string `sql:"pk" validate:"presence"`   // string field 'last_name' with size 128, NOT NULL  LastName string `sql:"size(128),notnull"`   // string field 'tag' with size 255, default value 'customer'  Tag string `sql:"size(255),default('customer')"`   // You can also combine tags, default value 'orange'  CombinedTags string `sql:"size(128),default('orange')"`  Birthday     time.Time   // timestamp field 'birthday'  Data         []byte      // data field 'data'  IsAdmin      bool        // boolean field 'is_admin'  Notes        string      // text field 'notes'   // You can alternatively define a var char as a string field by setting a size  Nick  string  `sql:"size(128)"`   // Validates number range  Balance int `validate:"range(10:20)"`   // These fields are auto updated on save  Created hood.Created  Updated hood.Updated   // ... and other built in types (int, uint, float...)} // Indexes are defined via the Indexed interface to avoid// polluting the table fields. func (table *Person) Indexes(indexes *hood.Indexes) {  indexes.Add("tag_index", "tag")// params: indexName, unique, columns...  indexes.AddUnique("name_index", "first_name", "last_name")}

資料移轉

你要先安裝hood tool ，然後運行

go get github.com/eaigner/hoodcd $GOPATH/src/github.com/eaigner/hood./install.sh<

例子

下面是一個使用例子

package main import (    "hood") func main() {    // Open a DB connection, use New() alternatively for unregistered dialects    hd, err := hood.Open("postgres", "user=hood dbname=hood_test sslmode=disable")    if err != nil {        panic(err)    }     // Create a table    type Fruit struct {        Id    hood.Id        Name  string `validate:"presence"`        Color string    }     err = hd.CreateTable(&Fruit{})    if err != nil {        panic(err)    }     fruits := []Fruit{        Fruit{Name: "banana", Color: "yellow"},        Fruit{Name: "apple", Color: "red"},        Fruit{Name: "grapefruit", Color: "yellow"},        Fruit{Name: "grape", Color: "green"},        Fruit{Name: "pear", Color: "yellow"},    }     // Start a transaction    tx := hd.Begin()     ids, err := tx.SaveAll(&fruits)    if err != nil {        panic(err)    }     fmt.Println("inserted ids:", ids)// [1 2 3 4 5]     // Commit changes    err = tx.Commit()    if err != nil {        panic(err)    }     // Ids are automatically updated    if fruits[0].Id != 1 || fruits[1].Id != 2 || fruits[2].Id != 3 {        panic("id not set")    }     // If an id is already set, a call to save will result in an update    fruits[0].Color = "green"     ids, err = hd.SaveAll(&fruits)    if err != nil {        panic(err)    }     fmt.Println("updated ids:", ids)// [1 2 3 4 5]     if fruits[0].Id != 1 || fruits[1].Id != 2 || fruits[2].Id != 3 {        panic("id not set")    }     // Let's try to save a row that does not satisfy the required validations    _, err = hd.Save(&Fruit{})    if err == nil || err.Error() != "value not set" {        panic("does not satisfy validations, should not save")    }     // Find    //    // The markers are db agnostic, so you can always use '?'    // e.g. in Postgres they are replaced with $1, $2, ...    var results []Fruit    err = hd.Where("color", "=", "green").OrderBy("name").Limit(1).Find(&results)    if err != nil {        panic(err)    }     fmt.Println("results:", results)// [{1 banana green}]     // Delete    ids, err = hd.DeleteAll(&results)    if err != nil {        panic(err)    }     fmt.Println("deleted ids:", ids)// [1]     results = nil    err = hd.Find(&results)    if err != nil {        panic(err)    }     fmt.Println("results:", results)// [{2 apple red} {3 grapefruit yellow} {4 grape green} {5 pear yellow}]     // Drop    hd.DropTable(&Fruit{})}