GORM 配置

原文：https://gorm.io/docs/gorm_config.html

GORM provides Config can be used during initialization

​ GORM提供了Config可以在初始化时使用。

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type Config struct {
  SkipDefaultTransaction   bool
  NamingStrategy           schema.Namer
  Logger                   logger.Interface
  NowFunc                  func() time.Time
  DryRun                   bool
  PrepareStmt              bool
  DisableNestedTransaction bool
  AllowGlobalUpdate        bool
  DisableAutomaticPing     bool
  DisableForeignKeyConstraintWhenMigrating bool
}

SkipDefaultTransaction

GORM perform write (create/update/delete) operations run inside a transaction to ensure data consistency, you can disable it during initialization if it is not required

​ GORM在执行写（创建/更新/删除）操作时，会运行在一个事务中以确保数据一致性，如果在初始化时不需要，可以禁用它

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db, err := gorm.Open(sqlite.Open("gorm.db"), &gorm.Config{
  SkipDefaultTransaction: true,
})

NamingStrategy

GORM allows users to change the naming conventions by overriding the default NamingStrategy which need to implements interface Namer

​ GORM允许用户通过覆盖默认的NamingStrategy来改变命名约定，需要实现接口Namer

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type Namer interface {
  TableName(table string) string
  SchemaName(table string) string
  ColumnName(table, column string) string
  JoinTableName(table string) string
  RelationshipFKName(Relationship) string
  CheckerName(table, column string) string
  IndexName(table, column string) string
}

The default NamingStrategy also provides few options, like:

​ 默认的NamingStrategy还提供了一些选项，例如：

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db, err := gorm.Open(sqlite.Open("gorm.db"), &gorm.Config{
  NamingStrategy: schema.NamingStrategy{
    TablePrefix: "t_",   // table name prefix, table for `User` would be `t_users`
    SingularTable: true, // use singular table name, table for `User` would be `user` with this option enabled
    NoLowerCase: true, // skip the snake_casing of names
    NameReplacer: strings.NewReplacer("CID", "Cid"), // use name replacer to change struct/field name before convert it to db name
  },
})

Logger

Allow to change GORM’s default logger by overriding this option, refer Logger for more details

​ 允许通过覆盖此选项来更改GORM的默认日志记录器，有关更多详细信息，请参阅Logger

NowFunc

Change the function to be used when creating a new timestamp

​ 更改创建新时间戳时要使用的函数

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db, err := gorm.Open(sqlite.Open("gorm.db"), &gorm.Config{
  NowFunc: func() time.Time {
    return time.Now().Local()
  },
})

DryRun

Generate SQL without executing, can be used to prepare or test generated SQL, refer Session for details

​ 生成SQL而不执行，可用于准备或测试生成的SQL，有关详细信息，请参阅Session

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db, err := gorm.Open(sqlite.Open("gorm.db"), &gorm.Config{
  DryRun: false,
})

PrepareStmt

PreparedStmt creates a prepared statement when executing any SQL and caches them to speed up future calls, refer Session for details

​ PreparedStmt在执行任何SQL时创建一个预处理语句并将其缓存以加速未来的调用，有关详细信息，请参阅Session

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db, err := gorm.Open(sqlite.Open("gorm.db"), &gorm.Config{
  PrepareStmt: false,
})

DisableNestedTransaction

When using Transaction method inside a db transaction, GORM will use SavePoint(savedPointName), RollbackTo(savedPointName) to give you the nested transaction support, you could disable it by using the DisableNestedTransaction option, refer Session for details

​ 在使用db事务内的Transaction方法时，GORM将使用SavePoint(savedPointName)，RollbackTo(savedPointName)提供嵌套事务支持，您可以通过使用DisableNestedTransaction选项禁用它，有关详细信息，请参阅Session

AllowGlobalUpdate

Enable global update/delete, refer Session for details

​ 启用全局更新/删除，有关详细信息，请参阅Session

DisableAutomaticPing

GORM automatically ping database after initialized to check database availability, disable it by setting it to true

​ GORM在初始化后自动ping数据库以检查数据库可用性，通过将其设置为true禁用它

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db, err := gorm.Open(sqlite.Open("gorm.db"), &gorm.Config{
  DisableAutomaticPing: true,
})

DisableForeignKeyConstraintWhenMigrating

GORM creates database foreign key constraints automatically when AutoMigrate or CreateTable, disable this by setting it to true, refer Migration for details

​ GORM在AutoMigrate或CreateTable时自动创建数据库外键约束，禁用此选项，将其设置为true，有关详细信息，请参阅Migration

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db, err := gorm.Open(sqlite.Open("gorm.db"), &gorm.Config{
  DisableForeignKeyConstraintWhenMigrating: true,
})