Tag: sqlite3

使用房间数据库（房间持久性库）创建触发器

如何使用房间持久性库“ 创建触发器 ” CREATE TRIGGER IF NOT EXISTS delete_till_10 INSERT ON user WHEN (select count(*) from user)>9 BEGIN DELETE FROM user WHERE id IN (SELECT id FROM user ORDER BY id limit (select count(*) -9 from user)); END

查询树中的父母

我有数据库表任务如下。 SELECT _id,name,parentId FROM Task; _id name parentId ———- ——————– ———- 4 Software Development 5 Machine Learning 6 Programing 4 7 Build System 4 8 version control 4 9 Android App Developm 4 10 Udacity Cource 5 11 Mathematics 5 12 skLearn docs 5 13 problem solving 6 14 breakdown 13 15 language 6 16 […]