HarmonyOS应用开发实战：猫猫大作战-RdbPredicates 查询条件构建
前言RdbPredicates是关系型数据库的条件构建器用于指定查询、更新、删除的过滤条件。在「猫猫大作战」中RdbPredicates 用于查询某个玩家的历史记录、筛选高分对局等。一、基本条件import { relationalStore } from kit.ArkData; const predicates new relationalStore.RdbPredicates(GAME_RECORD); // 相等条件 predicates.equalTo(player_name, 小明); // 大于条件 predicates.greaterThan(score, 1000); // 复合条件 predicates.equalTo(player_name, 小明) .and() .greaterThan(score, 500) .and() .orderByDesc(game_date);二、常用方法方法作用示例equalTo(field, val)等于equalTo(player, 小明)notEqualTo(field, val)不等于notEqualTo(level, 0)greaterThan(field, val)大于greaterThan(score, 100)lessThan(field, val)小于lessThan(duration, 300)between(field, lo, hi)区间between(score, 100, 1000)in(field, vals)包含in(level, [1, 2, 3])like(field, pat)模糊匹配like(name, %明%)orderByDesc(field)降序orderByDesc(score)limit(cnt, off)分页limit(10, 0)三、查询指定玩家的高分记录async function queryPlayerHighScores( store: relationalStore.RdbStore, playerName: string, minScore: number ): PromiseGameRecord[] { const predicates new relationalStore.RdbPredicates(GAME_RECORD); predicates.equalTo(player_name, playerName); predicates.greaterThan(score, minScore); predicates.orderByDesc(score); predicates.limit(10, 0); const resultSet await store.query(predicates); return parseResultSet(resultSet); }四、删除和更新// 删除 30 天前的记录 const deletePred new relationalStore.RdbPredicates(GAME_RECORD); deletePred.lessThan(game_date, 2026-06-28); await store.delete(deletePred); // 批量更新玩家名称 const updatePred new relationalStore.RdbPredicates(GAME_RECORD); updatePred.equalTo(player_name, 旧名字); await store.update( { player_name: 新名字 }, updatePred );五、最佳实践链式调用多个条件用.and()连接分页查询必加limit防止全表扫描索引equalTo和orderBy的字段建索引参数化条件值用参数传递防 SQL 注入总结RdbPredicates 通过链式方法构建查询条件支持等值、范围、模糊匹配等常见操作。核心要点equalTo/greaterThan/between条件方法、.and()连接复合条件、orderBylimit排序分页。如果这篇文章对你有帮助欢迎点赞、收藏⭐、关注你的支持是我持续创作的动力相关资源RdbPredicates API 参考关系型数据库开发指南第 135 篇RDB第 137 篇ValuesBucket
