定义 Realm 对象模型 - Java SDK

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定义 Realm 对象

扩展 RealmObject
实施 RealmModel
列表
定义嵌入式对象字段
注解
主键
必填字段
可选字段
默认字段值
为字段创建索引
忽略字段
重命名字段
重命名类
从 Realm 模式中省略类

Atlas Device SDK 已弃用。有关详细信息，请参阅弃用页面。

定义 Realm 对象

要在应用程序中定义Realm 对象，请创建 RealmObject的子类或实现RealmModel。

重要

所有 Realm 对象都必须提供一个空的构造函数。
所有 Realm 对象都必须使用 Java 中的 public 可见性修饰符或 Kotlin 中的 open 可见性修饰符。

注意

类名不得超过 57 个 UTF-8 字符。

扩展 `RealmObject`

以下代码块显示了一个描述 Frog 的 Realm 对象。此 Frog 类可以存储在 Realm 中，因为它 extends RealmObject 类。

import io.realm.RealmObject;
// To add an object to your Realm Schema, extend RealmObject
public class Frog extends RealmObject {
    private String name;
    private int age;
    private String species;
    private String owner;
    public Frog(String name, int age, String species, String owner) {
        this.name = name;
        this.age = age;
        this.species = species;
        this.owner = owner;
    }
    public Frog(){} // RealmObject subclasses must provide an empty constructor
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public int getAge() { return age; }
    public void setAge(int age) { this.age = age; }
    public String getSpecies() { return species; }
    public void setSpecies(String species) { this.species = species; }
    public String getOwner() { return owner; }
    public void setOwner(String owner) { this.owner = owner; }
}

import io.realm.RealmObject
// providing default values for each constructor parameter
// fulfills the need for an empty constructor
open class Frog(
    var name: String? = null,
    var age: Int = 0,
    var species: String? = null,
    var owner: String? = null
) : RealmObject() // To add an object to your Realm Schema, extend RealmObject

实施 `RealmModel`

以下代码块显示了一个描述 Frog 的 Realm 对象。此 Frog 类可以存储在 Realm 中，因为它 implements RealmModel 类并使用 @RealmClass 注释：

import io.realm.RealmModel;
import io.realm.annotations.RealmClass;
@RealmClass
public class Frog implements RealmModel {
    private String name;
    private int age;
    private String species;
    private String owner;
    public Frog(String name, int age, String species, String owner) {
        this.name = name;
        this.age = age;
        this.species = species;
        this.owner = owner;
    }
    public Frog() {} // RealmObject subclasses must provide an empty constructor
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public int getAge() { return age; }
    public void setAge(int age) { this.age = age; }
    public String getSpecies() { return species; }
    public void setSpecies(String species) { this.species = species; }
    public String getOwner() { return owner; }
    public void setOwner(String owner) { this.owner = owner; }
}

重要

所有 Realm 对象都必须使用 public 可见性修饰符。

import io.realm.RealmModel
import io.realm.annotations.RealmClass
@RealmClass
open class Frog : RealmModel {
    var name: String? = null
    var age = 0
    var species: String? = null
    var owner: String? = null
    constructor(name: String?, age: Int, species: String?, owner: String?) {
        this.name = name
        this.age = age
        this.species = species
        this.owner = owner
    }
    constructor() {} // RealmObject subclasses must provide an empty constructor
}

重要

所有 Realm 对象都必须使用 open 可见性修饰符。

提示

使用 realMobject 方法

通过扩展 RealmObject 类创建 Realm 对象时，您可以在 Realm 对象实例上动态访问 RealmObject 类方法。Realm 对象由实现 RealmModel 创建，可通过 RealmObject 类静态访问这些相同的方法：

// With RealmObject
frogRealmObject.isValid();
frogRealmObject.addChangeListener(listener);
// With RealmModel
RealmObject.isValid(frogRealmModel);
RealmObject.addChangeListener(frogRealmModel, listener);

// With RealmObject
frogRealmObject?.isValid
frogRealmObject?.addChangeListener(listener)
// With RealmModel
RealmObject.isValid(frogRealmModel)
RealmObject.addChangeListener(frogRealmModel, listener)

列表

Realm 对象可以包含非 Realm 对象数据类型的列表：

与Realm对象列表不同，这些列表可以包含 null 值。如果不允许空值，请使用@Required注解。

import io.realm.RealmList;
import io.realm.RealmObject;
public class Frog extends RealmObject {
    private String name;
    private int age;
    private String species;
    private String owner;
    private RealmList<String> favoriteColors;
    public Frog(String name, int age, String species, String owner, RealmList<String> favoriteColors) {
        this.name = name;
        this.age = age;
        this.species = species;
        this.owner = owner;
        this.favoriteColors = favoriteColors;
    }
    public Frog(){} // RealmObject subclasses must provide an empty constructor
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public int getAge() { return age; }
    public void setAge(int age) { this.age = age; }
    public String getSpecies() { return species; }
    public void setSpecies(String species) { this.species = species; }
    public String getOwner() { return owner; }
    public void setOwner(String owner) { this.owner = owner; }
    public RealmList<String> getFavoriteColors() { return favoriteColors; }
    public void setFavoriteColors(RealmList<String> favoriteColors) { this.favoriteColors = favoriteColors; }
}

import io.realm.RealmList
import io.realm.RealmObject
open class Frog : RealmObject {
    var name: String? = null
    var age = 0
    var species: String? = null
    var owner: String? = null
    var favoriteColors : RealmList<String>? = null
    constructor(
        name: String?,
        age: Int,
        species: String?,
        owner: String?,
        favoriteColors: RealmList<String>?
    ) {
        this.name = name
        this.age = age
        this.species = species
        this.owner = owner
        this.favoriteColors = favoriteColors
    }
    constructor() {} // RealmObject subclasses must provide an empty constructor
}

提示

另请参阅：

数据类型：列表

定义嵌入式对象字段

Realm 提供了在其他对象中嵌套对象的功能。这有几个优点：

如果使用同步，则对象会转换为遵循非规范化数据模型的 MongoDB 文档。
当您删除包含另一个对象的对象时，删除操作会将两个对象都从 Realm 中删除，这样未使用的对象不会在 Realm 文件中累积，也不会占用用户移动设备上的宝贵空间。

要嵌入对象，请将您想要嵌套在另一个类中的类的@RealmClass注解的embedded属性设立为true ：

import io.realm.RealmObject;
import io.realm.annotations.RealmClass;
@RealmClass(embedded=true)
public class Fly extends RealmObject {
    private String name;
    public Fly(String name) {
        this.name = name;
    }
    public Fly() {} // RealmObject subclasses must provide an empty constructor
}

import io.realm.RealmObject
import io.realm.annotations.RealmClass
@RealmClass(embedded = true)
open class Fly : RealmObject {
    private var name: String? = null
    constructor(name: String?) {
        this.name = name
    }
    constructor() {} // RealmObject subclasses must provide an empty constructor
}

每当您从另一个类引用该类时，Realm 都会将被引用的类嵌入到封装类中，如下例所示：

import io.realm.RealmObject;
public class Frog extends RealmObject {
    private String name;
    private int age;
    private String species;
    private String owner;
    private Fly lastMeal;
    public Frog(String name, int age, String species, String owner, Fly lastMeal) {
        this.name = name;
        this.age = age;
        this.species = species;
        this.owner = owner;
        this.lastMeal = lastMeal;
    }
    public Frog(){} // RealmObject subclasses must provide an empty constructor
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public int getAge() { return age; }
    public void setAge(int age) { this.age = age; }
    public String getSpecies() { return species; }
    public void setSpecies(String species) { this.species = species; }
    public String getOwner() { return owner; }
    public void setOwner(String owner) { this.owner = owner; }
    public Fly getLastMeal() { return lastMeal; }
    public void setLastMeal(Fly lastMeal) { this.lastMeal = lastMeal; }
}

import io.realm.RealmObject
open class Frog : RealmObject {
    var name: String? = null
    var age = 0
    var species: String? = null
    var owner: String? = null
    var lastMeal: Fly? = null
    constructor(
        name: String?,
        age: Int,
        species: String?,
        owner: String?,
        lastMeal: Fly?
    ) {
        this.name = name
        this.age = age
        this.species = species
        this.owner = owner
        this.lastMeal = lastMeal
    }
    constructor() {} // RealmObject subclasses must provide an empty constructor
}

提示

另请参阅：

数据类型：嵌入式对象

注解

使用注解自定义 Realm 对象模型。

主键

版本 10.6.0 的新增功能：Realm 会自动索引主键字段。此前，Realm 仅自动索引 String 主键。

Realm 将标有 @PrimaryKey 注解的字段视为其相应对象模式的主键。主键受到以下限制：

您只能为每个对象模式定义一个主键。
主键值在 Realm 中对象的所有实例中必须是唯一的。尝试插入重复的主键值会导致RealmPrimaryKeyConstraintException。
主键值不可变。要更改某一对象的主键值，必须删除原始对象并插入具有其他主键值的新对象。
嵌入式对象无法定义主键。

您可以使用以下任何类型创建主键：

String
UUID
ObjectId
Integer or int
Long or long
Short or short
Byte or byte[]

非原始类型可以包含值null作为主键值，但仅限于特定类型的一个对象，因为每个主键值必须是唯一的。尝试将具有现有主键的对象插入到 Realm 将导致RealmPrimaryKeyConstraintException。

Realm 自动对主键字段创建索引，因此您可以根据主键有效地读取和修改对象。

将某一类型的任何对象添加到域后，您无法更改该对象类型的主键字段。如果您使用 Sync，则在后端模式中定义主键后，您将无法更改对象的主键字段。

嵌入式对象不能包含主键。

您可以选择使用 @PrimaryKey 注解将对象类型的主键定义为对象模式的一部分：

import io.realm.RealmObject;
import io.realm.annotations.PrimaryKey;
public class Frog extends RealmObject {
    @PrimaryKey private String name;
    private int age;
    private String species;
    private String owner;
    public Frog(String name, int age, String species, String owner) {
        this.name = name;
        this.age = age;
        this.species = species;
        this.owner = owner;
    }
    public Frog(){} // RealmObject subclasses must provide an empty constructor
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public int getAge() { return age; }
    public void setAge(int age) { this.age = age; }
    public String getSpecies() { return species; }
    public void setSpecies(String species) { this.species = species; }
    public String getOwner() { return owner; }
    public void setOwner(String owner) { this.owner = owner; }
}

import io.realm.RealmObject
import io.realm.annotations.PrimaryKey
open class Frog : RealmObject {
    @PrimaryKey var name : String? = null
    var age = 0
    var species: String? = null
    var owner: String? = null
    constructor(name: String?, age: Int, species: String?, owner: String?) {
        this.name = name
        this.age = age
        this.species = species
        this.owner = owner
    }
    constructor() {} // RealmObject subclasses must provide an empty constructor
}

必填字段

import io.realm.RealmObject;
import io.realm.annotations.Required;
public class Frog extends RealmObject {
    @Required private String name;
    private int age;
    private String species;
    private String owner;
    public Frog(String name, int age, String species, String owner) {
        this.name = name;
        this.age = age;
        this.species = species;
        this.owner = owner;
    }
    public Frog(){} // RealmObject subclasses must provide an empty constructor
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public int getAge() { return age; }
    public void setAge(int age) { this.age = age; }
    public String getSpecies() { return species; }
    public void setSpecies(String species) { this.species = species; }
    public String getOwner() { return owner; }
    public void setOwner(String owner) { this.owner = owner; }
}

import io.realm.RealmObject
import io.realm.annotations.Required
open class Frog : RealmObject {
    @Required var name: String? = null
    var age = 0
    var species: String? = null
    var owner: String? = null
    constructor(name: String?, age: Int, species: String?, owner: String?) {
        this.name = name
        this.age = age
        this.species = species
        this.owner = owner
    }
    constructor() {} // RealmObject subclasses must provide an empty constructor
}

可选字段

标有Java对象类型和Kotlin可空类型（以?结尾）的字段默认可为 null。默认，所有其他类型（基元、不可为 null 的Kotlin对象类型）都是必需的。您可以使用@Required注解标记可为 null 的字段，以防止该字段持有 null 值。 RealmList永远不能为 null，但您可以使用@Required注解来防止列表中的对象持有 null 值，即使基本类型允许这样做。您无法将RealmObject子类型的RealmList标记为必填项。

可以根据需要使用以下类型：

String
UUID
ObjectId
Integer
Long
Short
Byte or byte[]
Boolean
Float
Double
Date
RealmList

int 和 RealmList 类型等基元类型是隐式必需的。RealmObject 类型的字段始终可以为 null，并且不能设为必填字段。

重要

Kotlin 类型和可空性

在Kotlin中，除非您显式向类型添加?后缀，否则默认类型不可为空。您只能注解可为 null 的类型。在非空类型上使用@Required注解会导致编译失败。

默认情况下，可空字段在 Realm 中是可选的，除非使用@Required注解另行指定。以下类型可为 null：

String
Date
UUID
ObjectId
Integer
Long
Short
Byte or byte[]
Boolean
Float
Double

默认， int和long等基元类型不可为空，也不能设为可空，因为它们不能设立为空值。

在Kotlin中，仅当字段使用Kotlin?操作符但以下类型除外：

String
Date
UUID
ObjectId
Decimal128
RealmAny

您可以要求任意以 Kotlin ? 运算符结尾的类型，例如 Int?。

RealmList 类型默认不可为空，并且不能设为可为空。

默认字段值

要为字段指定默认值，请使用内置语言功能来分配默认值。

使用类构造函数分配默认值：

import io.realm.RealmObject;
public class Frog extends RealmObject {
    private String name = "Kitty";
    private int age;
    private String species;
    private String owner;
    public Frog(String name, int age, String species, String owner) {
        this.name = name;
        this.age = age;
        this.species = species;
        this.owner = owner;
    }
    public Frog(){} // RealmObject subclasses must provide an empty constructor
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public int getAge() { return age; }
    public void setAge(int age) { this.age = age; }
    public String getSpecies() { return species; }
    public void setSpecies(String species) { this.species = species; }
    public String getOwner() { return owner; }
    public void setOwner(String owner) { this.owner = owner; }
}

在字段声明中指定默认值：

import io.realm.RealmObject
open class Frog : RealmObject {
    var name = "Kitty"
    var age = 0
    var species: String? = null
    var owner: String? = null
    constructor(name: String, age: Int, species: String?, owner: String?) {
        this.name = name
        this.age = age
        this.species = species
        this.owner = owner
    }
    constructor() {} // RealmObject subclasses must provide an empty constructor
}

注意

默认值和可空性

虽然默认值可确保新创建的对象不能包含值null （除非您指定默认值null ），但它们不会影响字段的可空性。要将字段设为不可为空，请参阅必填字段。

为字段创建索引

Realm 中的索引支持高效执行查询。如果没有索引，Realm 就必须执行集合扫描（即扫描集合中的每个文档），以选择与查询相匹配的文档。如果查询存在适当的索引，Realm 就可以使用该索引来限制必须检查的文档数量。

索引是特殊的数据结构，它以易于遍历的形式存储一小部分 realm 数据。索引存储按字段值排序的特定字段的值。索引条目的排序支持高效的相等匹配和基于范围的查询操作。

添加索引可以加快某些查询的速度，但代价是写入速度稍慢，并增加存储和内存开销。索引需要 Realm 文件的空间，因此为属性添加索引会增加 Realm 文件消耗的磁盘空间。每个索引条目至少有 12 个字节。

您可以为以下类型的字段建立索引：

String
UUID
ObjectId
Integer or int
Long or long
Short or short
Byte or byte[]
Boolean or bool
Date
RealmAny

Realm 为带有 @Index 注解的字段创建索引。

要为字段建立索引，请使用 @Index 注解：

import io.realm.RealmObject;
import io.realm.annotations.Index;
public class Frog extends RealmObject {
    private String name;
    private int age;
    @Index private String species;
    private String owner;
    public Frog(String name, int age, String species, String owner) {
        this.name = name;
        this.age = age;
        this.species = species;
        this.owner = owner;
    }
    public Frog(){} // RealmObject subclasses must provide an empty constructor
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public int getAge() { return age; }
    public void setAge(int age) { this.age = age; }
    public String getSpecies() { return species; }
    public void setSpecies(String species) { this.species = species; }
    public String getOwner() { return owner; }
    public void setOwner(String owner) { this.owner = owner; }
}

import io.realm.RealmObject
import io.realm.annotations.Index
open class Frog : RealmObject {
    var name: String? = null
    var age = 0
    @Index var species : String? = null
    var owner: String? = null
    constructor(name: String?, age: Int, species: String?, owner: String?) {
        this.name = name
        this.age = age
        this.species = species
        this.owner = owner
    }
    constructor() {} // RealmObject subclasses must provide an empty constructor
}

忽略字段

如果您不想将模型中的某个字段保存到 Realm，则可以忽略该字段。

使用 @Ignore 注解，忽略 Realm 对象模型中的字段：

import io.realm.RealmObject;
import io.realm.annotations.Ignore;
public class Frog extends RealmObject {
    private String name;
    private int age;
    private String species;
    // can you ever really own a frog persistently?
    @Ignore private String owner;
    public Frog(String name, int age, String species, String owner) {
        this.name = name;
        this.age = age;
        this.species = species;
        this.owner = owner;
    }
    public Frog(){} // RealmObject subclasses must provide an empty constructor
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public int getAge() { return age; }
    public void setAge(int age) { this.age = age; }
    public String getSpecies() { return species; }
    public void setSpecies(String species) { this.species = species; }
    public String getOwner() { return owner; }
    public void setOwner(String owner) { this.owner = owner; }
}

import io.realm.RealmObject
import io.realm.annotations.Ignore
open class Frog : RealmObject {
    var name: String? = null
    var age = 0
    var species: String? = null
    // can you ever really own a frog persistently?
    @Ignore var owner  : String? = null
    constructor(name: String?, age: Int, species: String?, owner: String?) {
        this.name = name
        this.age = age
        this.species = species
        this.owner = owner
    }
    constructor() {} // RealmObject subclasses must provide an empty constructor
}

注意

SDK 会忽略静态字段和瞬态字段

标记为 static 或 transient 的字段将始终被忽略，并且不需要 @Ignore 注释。

重命名字段

默认情况下，Realm 在内部使用模型类中定义的名称来表示字段。在某些情况下，您可能想要更改此行为：

要便于在具有不同命名约定的多个平台上工作。
在不强制迁移的情况下更改 Kotlin 中的字段名称。

选择与模型类中使用的名称不同的内部名称，会产生以下影响：

在创建类和字段时，迁移必须使用内部名称。
模式错误报告将使用内部名称。

使用 @RealmField 注解，以重命名字段：

import io.realm.RealmObject;
import io.realm.annotations.RealmField;
public class Frog extends RealmObject {
    private String name;
    private int age;
    @RealmField("latinName") private String species;
    private String owner;
    public Frog(String name, int age, String species, String owner) {
        this.name = name;
        this.age = age;
        this.species = species;
        this.owner = owner;
    }
    public Frog(){} // RealmObject subclasses must provide an empty constructor
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public int getAge() { return age; }
    public void setAge(int age) { this.age = age; }
    public String getSpecies() { return species; }
    public void setSpecies(String species) { this.species = species; }
    public String getOwner() { return owner; }
    public void setOwner(String owner) { this.owner = owner; }
}

import io.realm.RealmObject
import io.realm.annotations.RealmField
open class Frog : RealmObject {
    var name: String? = null
    var age = 0
    @RealmField("latinName") var species: String? = null
    var owner: String? = null
    constructor(name: String?, age: Int, species: String?, owner: String?) {
        this.name = name
        this.age = age
        this.species = species
        this.owner = owner
    }
    constructor() {} // RealmObject subclasses must provide an empty constructor
}

您还可以在模块或类级别指定命名策略，以变更 Realm 解释字段名称的方式。

您可以在模块级别定义命名策略，这将影响模块中包含的所有类：

import io.realm.annotations.RealmModule;
import io.realm.annotations.RealmNamingPolicy;
@RealmModule(
        allClasses = true,
        classNamingPolicy = RealmNamingPolicy.LOWER_CASE_WITH_UNDERSCORES,
        fieldNamingPolicy = RealmNamingPolicy.LOWER_CASE_WITH_UNDERSCORES
)
public class MyModule {
}

import io.realm.annotations.RealmModule
import io.realm.annotations.RealmNamingPolicy
@RealmModule(
    allClasses = true,
    classNamingPolicy = RealmNamingPolicy.LOWER_CASE_WITH_UNDERSCORES,
    fieldNamingPolicy = RealmNamingPolicy.LOWER_CASE_WITH_UNDERSCORES
)
open class MyModule

您还可以在类级别定义命名策略，该策略会覆盖模块级别的设置：

import io.realm.RealmObject;
import io.realm.annotations.RealmClass;
import io.realm.annotations.RealmNamingPolicy;
@RealmClass(fieldNamingPolicy = RealmNamingPolicy.PASCAL_CASE)
public class Frog extends RealmObject {
    private String name;
    private int age;
    private String species;
    private String owner;
    public Frog(String name, int age, String species, String owner) {
        this.name = name;
        this.age = age;
        this.species = species;
        this.owner = owner;
    }
    public Frog(){} // RealmObject subclasses must provide an empty constructor
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public int getAge() { return age; }
    public void setAge(int age) { this.age = age; }
    public String getSpecies() { return species; }
    public void setSpecies(String species) { this.species = species; }
    public String getOwner() { return owner; }
    public void setOwner(String owner) { this.owner = owner; }
}

import io.realm.RealmObject
import io.realm.annotations.RealmClass
import io.realm.annotations.RealmNamingPolicy
@RealmClass(fieldNamingPolicy = RealmNamingPolicy.PASCAL_CASE)
open class Frog : RealmObject {
    var name: String? = null
    var age = 0
    var species: String? = null
    var owner: String? = null
    constructor(name: String?, age: Int, species: String?, owner: String?) {
        this.name = name
        this.age = age
        this.species = species
        this.owner = owner
    }
    constructor() {} // RealmObject subclasses must provide an empty constructor
}

重命名类

默认情况下，Realm 在内部使用模型类中定义的名称来表示类。在某些情况下，您可能想要更改此行为：

支持不同软件包中具有相同简单名称的多个模型类。
要便于在具有不同命名约定的多个平台上工作。
要使用长度大于 Realm 执行的 57 个字符限制的类名。
在 Kotlin 中更改类名而不强制迁移。

使用 @RealmClass 注释重命名一个类：

import io.realm.RealmObject;
import io.realm.annotations.RealmClass;
@RealmClass(name = "ShortBodiedTaillessAmphibian")
public class Frog extends RealmObject {
    private String name;
    private int age;
    private String species;
    private String owner;
    public Frog(String name, int age, String species, String owner) {
        this.name = name;
        this.age = age;
        this.species = species;
        this.owner = owner;
    }
    public Frog(){} // RealmObject subclasses must provide an empty constructor
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public int getAge() { return age; }
    public void setAge(int age) { this.age = age; }
    public String getSpecies() { return species; }
    public void setSpecies(String species) { this.species = species; }
    public String getOwner() { return owner; }
    public void setOwner(String owner) { this.owner = owner; }
}

import io.realm.RealmObject
import io.realm.annotations.RealmClass
@RealmClass(name = "Short_Bodied_Tailless_Amphibian")
open class Frog : RealmObject {
    var name: String? = null
    var age = 0
    var species: String? = null
    var owner: String? = null
    constructor(name: String?, age: Int, species: String?, owner: String?) {
        this.name = name
        this.age = age
        this.species = species
        this.owner = owner
    }
    constructor() {} // RealmObject subclasses must provide an empty constructor
}

从 Realm 模式中省略类

默认情况下，应用程序的 Realm 模式包括所有扩展 RealmObject 的类。如果您只想在 Realm 模式中包含扩展 RealmObject 的类的子集，则可以在模块中包含该类的子集，并使用该模块打开 Realm：

import io.realm.annotations.RealmModule;
@RealmModule(classes = { Frog.class, Fly.class })
public class MyModule {
}

import io.realm.annotations.RealmModule
@RealmModule(classes = [Frog::class, Fly::class])
open class MyModule

后退

模型数据

来年

关系

定义 Realm 对象

重要

注意

扩展 RealmObject

实施 RealmModel

重要

重要

提示

使用 realMobject 方法

列表

提示

另请参阅：

定义嵌入式对象字段

提示

另请参阅：

注解

主键

必填字段

可选字段

重要

Kotlin 类型和可空性

默认字段值

注意

默认值和可空性

为字段创建索引

忽略字段

注意

SDK 会忽略静态字段和瞬态字段

重命名字段

重命名类

从 Realm 模式中省略类

扩展 `RealmObject`

实施 `RealmModel`