查询操作符

RxDB 使用统一的 RuleGroup 结构描述查询条件。

基础结构

interface Rule<T = any, K extends keyof T = keyof T> {
  field: K;
  operator: OperatorName;
  value?: any;
  where?: RuleGroup<any>;
}

interface RuleGroup<T = any> {
  combinator: 'and' | 'or';
  rules: Array<RuleGroup<T> | Rule<T>>;
}

操作符分类

• 比较：=、!=、<、>、<=、>=
• 集合：in、notIn
• 区间：between、notBetween
• 字符串：contains、notContains、startsWith、notStartsWith、endsWith、notEndsWith
• 存在性：exists、notExists

基础示例

const where = {
  combinator: 'and',
  rules: [
    { field: 'completed', operator: '=', value: false },
    { field: 'title', operator: 'contains', value: keyword }
  ]
} as const;

嵌套组合

const where = {
  combinator: 'and',
  rules: [
    { field: 'completed', operator: '=', value: false },
    {
      combinator: 'or',
      rules: [
        { field: 'priority', operator: '=', value: 'high' },
        { field: 'dueDate', operator: '<=', value: new Date() }
      ]
    }
  ]
} as const;

关系字段

const where = {
  combinator: 'and',
  rules: [{ field: 'owner.name', operator: 'startsWith', value: 'A' }]
};

exists / notExists 的正确写法

这里不要再把子查询条件塞进 value。当前实现的正确结构是 where：

const where = {
  combinator: 'and',
  rules: [
    {
      field: 'children',
      operator: 'exists',
      where: {
        combinator: 'and',
        rules: [{ field: 'enabled', operator: '=', value: true }]
      }
    }
  ]
};

null 判断

{ field: 'parentId', operator: '=', value: null }
{ field: 'email', operator: '!=', value: null }

参考

• exists-operator
• find