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@ -1,19 +1,3 @@
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/*
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* Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package net.micode.notes.data;
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import android.content.ContentValues;
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@ -28,188 +12,253 @@ import net.micode.notes.data.Notes.NoteColumns;
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public class NotesDatabaseHelper extends SQLiteOpenHelper {
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// 数据库帮助类，用于管理名为 note.db 的 SQLite 数据库。
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// 它继承自 SQLiteOpenHelper 类，这是 Android提供的一个方便的工具类，用于管理数据库的创建和版本更新.
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// 数据库的基本信息；数据库名称和版本信息（在创建实例对象时会用到）
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private static final String DB_NAME = "note.db";
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private static final int DB_VERSION = 4;
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//内部接口：个人理解为两个表名，一个note，一个data
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public interface TABLE {
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public static final String NOTE = "note";
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public static final String DATA = "data";
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}
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//一个标签，方便日志输出时识别出信息来自哪里
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private static final String TAG = "NotesDatabaseHelper";
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//静态所有变量，提供一个全局访问点来获取数据库辅助类的唯一实例，使得在应用的任何地方都可以方便地使用它
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private static NotesDatabaseHelper mInstance;
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/* 以下都是一些SQL语句，辅助我们来对数据库进行操作 */
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//创建note表的语句，这里的NoteColumns就是我们刚刚在Notes中定义的一个接口，里面定义了一系列静态的数据库表中的列名
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private static final String CREATE_NOTE_TABLE_SQL =
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"CREATE TABLE " + TABLE.NOTE + "(" +
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NoteColumns.ID + " INTEGER PRIMARY KEY," +
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NoteColumns.PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.ALERTED_DATE + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.BG_COLOR_ID + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
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NoteColumns.HAS_ATTACHMENT + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
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NoteColumns.NOTES_COUNT + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.SNIPPET + " TEXT NOT NULL DEFAULT ''," +
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NoteColumns.TYPE + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.WIDGET_ID + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.WIDGET_TYPE + " INTEGER NOT NULL DEFAULT -1," +
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NoteColumns.SYNC_ID + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.LOCAL_MODIFIED + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.ORIGIN_PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT ''," +
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NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0" +
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")";
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"CREATE TABLE " + TABLE.NOTE + "(" +
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NoteColumns.ID + " INTEGER PRIMARY KEY," +
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NoteColumns.PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.ALERTED_DATE + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.BG_COLOR_ID + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
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NoteColumns.HAS_ATTACHMENT + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
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NoteColumns.NOTES_COUNT + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.SNIPPET + " TEXT NOT NULL DEFAULT ''," +
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NoteColumns.TYPE + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.WIDGET_ID + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.WIDGET_TYPE + " INTEGER NOT NULL DEFAULT -1," +
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NoteColumns.SYNC_ID + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.LOCAL_MODIFIED + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.ORIGIN_PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT ''," +
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NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0" +
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")";
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//同上，创建data表的语句，这里的DataColumns就是我们刚刚在Notes中定义的一个接口，里面定义了一系列静态的数据库表中的列名
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private static final String CREATE_DATA_TABLE_SQL =
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"CREATE TABLE " + TABLE.DATA + "(" +
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DataColumns.ID + " INTEGER PRIMARY KEY," +
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DataColumns.MIME_TYPE + " TEXT NOT NULL," +
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DataColumns.NOTE_ID + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
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NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
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DataColumns.CONTENT + " TEXT NOT NULL DEFAULT ''," +
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DataColumns.DATA1 + " INTEGER," +
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DataColumns.DATA2 + " INTEGER," +
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DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," +
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DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," +
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DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" +
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")";
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"CREATE TABLE " + TABLE.DATA + "(" +
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DataColumns.ID + " INTEGER PRIMARY KEY," +
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DataColumns.MIME_TYPE + " TEXT NOT NULL," +
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DataColumns.NOTE_ID + " INTEGER NOT NULL DEFAULT 0," +
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NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
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NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
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DataColumns.CONTENT + " TEXT NOT NULL DEFAULT ''," +
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DataColumns.DATA1 + " INTEGER," +
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DataColumns.DATA2 + " INTEGER," +
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DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," +
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DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," +
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DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" +
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")";
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// 功能简介：
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// 创建一个以note的ID为索引
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// 解读：
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// 用于在TABLE.DATA表上创建一个名为note_id_index的索引。
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// 这个索引是基于DataColumns.NOTE_ID列的。IF NOT EXISTS确保了如果索引已经存在，那么就不会尝试重新创建它，避免了可能的错误。
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// 索引通常用于提高查询性能，特别是在对某个字段进行频繁查询时。
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private static final String CREATE_DATA_NOTE_ID_INDEX_SQL =
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"CREATE INDEX IF NOT EXISTS note_id_index ON " +
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TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";
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"CREATE INDEX IF NOT EXISTS note_id_index ON " +
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TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";
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/* 以下是一些对便签增删改定义的触发器 */
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/* 总结
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* 这些触发器都是用来维护NOTE表和与之相关联的DATA表之间数据一致性的。
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* 当在NOTE表中发生删除或更新操作时，这些触发器会自动执行相应的数据清理或更新操作，确保数据库中的数据保持正确和一致。
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* 特别是在处理文件夹和回收站等逻辑时，这些触发器起到了非常重要的作用，可以自动管理数据的移动和删除。*/
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/**
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* Increase folder's note count when move note to the folder
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*/
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// 功能简介：
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// 添加触发器：增加文件夹的便签个数记录（因为我们会移动便签进入文件夹，这时候文件夹的计数要进行更新）
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// 解读：
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// 定义了一个SQL触发器increase_folder_count_on_update。
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// 触发器是一种特殊的存储过程，它会在指定表上的指定事件（如INSERT、UPDATE、DELETE）发生时自动执行。
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// 这个触发器会在TABLE.NOTE表的NoteColumns.PARENT_ID字段更新后执行。
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// 触发器的逻辑是：当某个笔记的PARENT_ID（即父文件夹ID）被更新时，它会找到对应的文件夹（通过新的PARENT_ID），并将该文件夹的NOTES_COUNT（即笔记数）增加1。
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private static final String NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
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"CREATE TRIGGER increase_folder_count_on_update "+
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" AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
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" BEGIN " +
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" UPDATE " + TABLE.NOTE +
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" SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
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" WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
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" END";
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"CREATE TRIGGER increase_folder_count_on_update "+
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" AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
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" BEGIN " +
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" UPDATE " + TABLE.NOTE +
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" SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
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" WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
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" END";
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/**
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* Decrease folder's note count when move note from folder
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*/
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// 功能简介：（触发器和上面的 “增加文件夹的便签个数记录” 同理，就不细节解读了）
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// 添加触发器：减少文件夹的便签个数记录（因为我们会移动便签移出文件夹，这时候文件夹的计数要进行更新）
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private static final String NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
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"CREATE TRIGGER decrease_folder_count_on_update " +
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" AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
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" BEGIN " +
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" UPDATE " + TABLE.NOTE +
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" SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
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" WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
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" AND " + NoteColumns.NOTES_COUNT + ">0" + ";" +
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" END";
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"CREATE TRIGGER decrease_folder_count_on_update " +
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" AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
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" BEGIN " +
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" UPDATE " + TABLE.NOTE +
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" SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
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" WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
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" AND " + NoteColumns.NOTES_COUNT + ">0" + ";" +
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" END";
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/**
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* Increase folder's note count when insert new note to the folder
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*/
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// 功能简介：（触发器原理和上面的 “增加文件夹的便签个数记录” 同理，就不细节解读了）
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// 添加触发器：当我们在文件夹插入便签时，增加文件夹的便签个数记录
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private static final String NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER =
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"CREATE TRIGGER increase_folder_count_on_insert " +
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" AFTER INSERT ON " + TABLE.NOTE +
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" BEGIN " +
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" UPDATE " + TABLE.NOTE +
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" SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
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" WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
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" END";
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"CREATE TRIGGER increase_folder_count_on_insert " +
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" AFTER INSERT ON " + TABLE.NOTE +
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" BEGIN " +
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" UPDATE " + TABLE.NOTE +
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" SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
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" WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
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" END";
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/**
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* Decrease folder's note count when delete note from the folder
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*/
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// 功能简介：（触发器原理和上面的 “增加文件夹的便签个数记录” 同理，就不细节解读了）
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// 添加触发器：当我们在文件夹删除便签时，减少文件夹的便签个数记录
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private static final String NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER =
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"CREATE TRIGGER decrease_folder_count_on_delete " +
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" AFTER DELETE ON " + TABLE.NOTE +
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" BEGIN " +
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" UPDATE " + TABLE.NOTE +
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" SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
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" WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
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" AND " + NoteColumns.NOTES_COUNT + ">0;" +
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" END";
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"CREATE TRIGGER decrease_folder_count_on_delete " +
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" AFTER DELETE ON " + TABLE.NOTE +
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" BEGIN " +
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" UPDATE " + TABLE.NOTE +
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" SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
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" WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
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" AND " + NoteColumns.NOTES_COUNT + ">0;" +
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" END";
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/**
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* Update note's content when insert data with type {@link DataConstants#NOTE}
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*/
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// 功能简介：
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// 添加触发器：当向DATA表中插入类型为NOTE（便签）的数据时，更新note表对应的笔记内容。
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// 解读：
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// 在DATA表上进行INSERT操作后，如果新插入的数据的MIME_TYPE为NOTE，则触发此操作。
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// 它会更新NOTE表，将与新插入数据相关联的标签的SNIPPET（摘要）字段设置为新插入数据的CONTENT字段的值
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private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER =
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"CREATE TRIGGER update_note_content_on_insert " +
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" AFTER INSERT ON " + TABLE.DATA +
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" WHEN new." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
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" BEGIN" +
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" UPDATE " + TABLE.NOTE +
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" SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
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" WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
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" END";
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"CREATE TRIGGER update_note_content_on_insert " +
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" AFTER INSERT ON " + TABLE.DATA +
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" WHEN new." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
|
|
|
|
|
" BEGIN" +
|
|
|
|
|
" UPDATE " + TABLE.NOTE +
|
|
|
|
|
" SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
|
|
|
|
|
" WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
|
|
|
|
|
" END";
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* Update note's content when data with {@link DataConstants#NOTE} type has changed
|
|
|
|
|
*/
|
|
|
|
|
// 功能简介：
|
|
|
|
|
// 添加触发器：当DATA表中，类型为NOTE（便签）的数据更改时，更新note表对应的笔记内容。
|
|
|
|
|
// 解读：
|
|
|
|
|
// 在DATA表上进行UPDATE操作后，如果更新前的数据的MIME_TYPE为NOTE，则触发此操作。
|
|
|
|
|
// 它会更新NOTE表，将与更新后的数据相关联的笔记的SNIPPET字段设置为新数据的CONTENT字段的值
|
|
|
|
|
private static final String DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER =
|
|
|
|
|
"CREATE TRIGGER update_note_content_on_update " +
|
|
|
|
|
" AFTER UPDATE ON " + TABLE.DATA +
|
|
|
|
|
" WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
|
|
|
|
|
" BEGIN" +
|
|
|
|
|
" UPDATE " + TABLE.NOTE +
|
|
|
|
|
" SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
|
|
|
|
|
" WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
|
|
|
|
|
" END";
|
|
|
|
|
"CREATE TRIGGER update_note_content_on_update " +
|
|
|
|
|
" AFTER UPDATE ON " + TABLE.DATA +
|
|
|
|
|
" WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
|
|
|
|
|
" BEGIN" +
|
|
|
|
|
" UPDATE " + TABLE.NOTE +
|
|
|
|
|
" SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
|
|
|
|
|
" WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
|
|
|
|
|
" END";
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* Update note's content when data with {@link DataConstants#NOTE} type has deleted
|
|
|
|
|
*/
|
|
|
|
|
// 功能简介：
|
|
|
|
|
// 添加触发器：当DATA表中，类型为NOTE（便签）的数据删除时，更新note表对应的笔记内容（置空）。
|
|
|
|
|
// 解读：
|
|
|
|
|
// 在DATA表上进行DELETE操作后，如果删除的数据的MIME_TYPE为NOTE，则触发此操作。
|
|
|
|
|
// 它会更新NOTE表，将与删除的数据相关联的笔记的SNIPPET字段设置为空字符串。
|
|
|
|
|
private static final String DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER =
|
|
|
|
|
"CREATE TRIGGER update_note_content_on_delete " +
|
|
|
|
|
" AFTER delete ON " + TABLE.DATA +
|
|
|
|
|
" WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
|
|
|
|
|
" BEGIN" +
|
|
|
|
|
" UPDATE " + TABLE.NOTE +
|
|
|
|
|
" SET " + NoteColumns.SNIPPET + "=''" +
|
|
|
|
|
" WHERE " + NoteColumns.ID + "=old." + DataColumns.NOTE_ID + ";" +
|
|
|
|
|
" END";
|
|
|
|
|
"CREATE TRIGGER update_note_content_on_delete " +
|
|
|
|
|
" AFTER delete ON " + TABLE.DATA +
|
|
|
|
|
" WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
|
|
|
|
|
" BEGIN" +
|
|
|
|
|
" UPDATE " + TABLE.NOTE +
|
|
|
|
|
" SET " + NoteColumns.SNIPPET + "=''" +
|
|
|
|
|
" WHERE " + NoteColumns.ID + "=old." + DataColumns.NOTE_ID + ";" +
|
|
|
|
|
" END";
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* Delete datas belong to note which has been deleted
|
|
|
|
|
*/
|
|
|
|
|
// 功能简介：
|
|
|
|
|
// 添加触发器：当从NOTE表中删除笔记时，删除与该笔记相关联的数据（就是删除data表中为该note的数据）
|
|
|
|
|
// 解读：
|
|
|
|
|
// 在NOTE表上进行DELETE操作后，此触发器被激活。
|
|
|
|
|
// 它会从DATA表中删除所有与已删除的笔记（由old.ID表示）相关联的数据行（通过比较DATA表中的NOTE_ID字段与已删除笔记的ID来实现）
|
|
|
|
|
private static final String NOTE_DELETE_DATA_ON_DELETE_TRIGGER =
|
|
|
|
|
"CREATE TRIGGER delete_data_on_delete " +
|
|
|
|
|
" AFTER DELETE ON " + TABLE.NOTE +
|
|
|
|
|
" BEGIN" +
|
|
|
|
|
" DELETE FROM " + TABLE.DATA +
|
|
|
|
|
" WHERE " + DataColumns.NOTE_ID + "=old." + NoteColumns.ID + ";" +
|
|
|
|
|
" END";
|
|
|
|
|
"CREATE TRIGGER delete_data_on_delete " +
|
|
|
|
|
" AFTER DELETE ON " + TABLE.NOTE +
|
|
|
|
|
" BEGIN" +
|
|
|
|
|
" DELETE FROM " + TABLE.DATA +
|
|
|
|
|
" WHERE " + DataColumns.NOTE_ID + "=old." + NoteColumns.ID + ";" +
|
|
|
|
|
" END";
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* Delete notes belong to folder which has been deleted
|
|
|
|
|
*/
|
|
|
|
|
// 功能简介：
|
|
|
|
|
// 添加触发器：当从NOTE表中删除一个文件夹时，删除该文件夹下的所有笔记。
|
|
|
|
|
// 解读：
|
|
|
|
|
// 在NOTE表上进行DELETE操作后，如果删除的是一个文件夹（由old.ID表示）
|
|
|
|
|
// 触发器会删除所有以该文件夹为父级（PARENT_ID）的笔记（通过比较NOTE表中的PARENT_ID字段与已删除文件夹的ID来实现）
|
|
|
|
|
private static final String FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER =
|
|
|
|
|
"CREATE TRIGGER folder_delete_notes_on_delete " +
|
|
|
|
|
" AFTER DELETE ON " + TABLE.NOTE +
|
|
|
|
|
" BEGIN" +
|
|
|
|
|
" DELETE FROM " + TABLE.NOTE +
|
|
|
|
|
" WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
|
|
|
|
|
" END";
|
|
|
|
|
"CREATE TRIGGER folder_delete_notes_on_delete " +
|
|
|
|
|
" AFTER DELETE ON " + TABLE.NOTE +
|
|
|
|
|
" BEGIN" +
|
|
|
|
|
" DELETE FROM " + TABLE.NOTE +
|
|
|
|
|
" WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
|
|
|
|
|
" END";
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* Move notes belong to folder which has been moved to trash folder
|
|
|
|
|
*/
|
|
|
|
|
// 功能简介：
|
|
|
|
|
// 添加触发器：当某个文件夹被移动到回收站时，移动该文件夹下的所有笔记到回收站
|
|
|
|
|
// 解读：
|
|
|
|
|
// 在NOTE表上进行UPDATE操作后，如果某个文件夹的新PARENT_ID字段值等于回收站的ID（Notes.ID_TRASH_FOLER）
|
|
|
|
|
// 触发器会更新所有以该文件夹为父级（PARENT_ID）的笔记，将它们也移动到回收站。
|
|
|
|
|
private static final String FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER =
|
|
|
|
|
"CREATE TRIGGER folder_move_notes_on_trash " +
|
|
|
|
|
" AFTER UPDATE ON " + TABLE.NOTE +
|
|
|
|
|
" WHEN new." + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
|
|
|
|
|
" BEGIN" +
|
|
|
|
|
" UPDATE " + TABLE.NOTE +
|
|
|
|
|
" SET " + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
|
|
|
|
|
" WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
|
|
|
|
|
" END";
|
|
|
|
|
|
|
|
|
|
"CREATE TRIGGER folder_move_notes_on_trash " +
|
|
|
|
|
" AFTER UPDATE ON " + TABLE.NOTE +
|
|
|
|
|
" WHEN new." + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
|
|
|
|
|
" BEGIN" +
|
|
|
|
|
" UPDATE " + TABLE.NOTE +
|
|
|
|
|
" SET " + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
|
|
|
|
|
" WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
|
|
|
|
|
" END";
|
|
|
|
|
|
|
|
|
|
// 构造器
|
|
|
|
|
public NotesDatabaseHelper(Context context) {
|
|
|
|
|
super(context, DB_NAME, null, DB_VERSION);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// 创建note（标签）表
|
|
|
|
|
public void createNoteTable(SQLiteDatabase db) {
|
|
|
|
|
db.execSQL(CREATE_NOTE_TABLE_SQL);
|
|
|
|
|
reCreateNoteTableTriggers(db);
|
|
|
|
|
@ -217,6 +266,9 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
|
|
|
|
|
Log.d(TAG, "note table has been created");
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// 重新创建或更新与笔记表相关的触发器。
|
|
|
|
|
// 首先，使用DROP TRIGGER IF EXISTS语句删除已存在的触发器。确保在重新创建触发器之前，不存在同名的触发器。
|
|
|
|
|
// 然后，使用db.execSQL()方法执行预定义的SQL语句，这些语句用于创建新的触发器。
|
|
|
|
|
private void reCreateNoteTableTriggers(SQLiteDatabase db) {
|
|
|
|
|
db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_update");
|
|
|
|
|
db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_update");
|
|
|
|
|
@ -235,6 +287,17 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
|
|
|
|
|
db.execSQL(FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* 以下部分是操作SQLite数据库部分 */
|
|
|
|
|
// 功能简介：
|
|
|
|
|
// 创建通话记录文件夹、默认文件夹、临时文件夹和回收站，并插入相关数据
|
|
|
|
|
// 具体解读：
|
|
|
|
|
// ContentValues是一个用于存储键值对的类，常用于SQLite数据库的插入操作
|
|
|
|
|
// values.put方法可以向ContentValues对象中添加数据。
|
|
|
|
|
// NoteColumns.ID是存储文件夹ID的列名，Notes.ID_CALL_RECORD_FOLDER是通话记录文件夹的ID。
|
|
|
|
|
// NoteColumns.TYPE是存储文件夹类型的列名，Notes.TYPE_SYSTEM表示这是一个系统文件夹。
|
|
|
|
|
// 使用db.insert方法将values中的数据插入到TABLE.NOTE（即标签表）中。
|
|
|
|
|
// 每次插入新数据前，都使用values.clear()方法清除ContentValues对象中的旧数据，确保不会重复插入旧数据。
|
|
|
|
|
// 然后分别创建默认文件夹、临时文件夹和回收站，并以同样的方法插入数据。
|
|
|
|
|
private void createSystemFolder(SQLiteDatabase db) {
|
|
|
|
|
ContentValues values = new ContentValues();
|
|
|
|
|
|
|
|
|
|
@ -248,6 +311,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
|
|
|
|
|
/**
|
|
|
|
|
* root folder which is default folder
|
|
|
|
|
*/
|
|
|
|
|
// 创建默认文件夹：重复上述步骤，但这次是为根文件夹插入数据。
|
|
|
|
|
values.clear();
|
|
|
|
|
values.put(NoteColumns.ID, Notes.ID_ROOT_FOLDER);
|
|
|
|
|
values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
|
|
|
|
|
@ -256,6 +320,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
|
|
|
|
|
/**
|
|
|
|
|
* temporary folder which is used for moving note
|
|
|
|
|
*/
|
|
|
|
|
// 创建“临时”文件夹：同样地，为临时文件夹插入数据。
|
|
|
|
|
values.clear();
|
|
|
|
|
values.put(NoteColumns.ID, Notes.ID_TEMPARAY_FOLDER);
|
|
|
|
|
values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
|
|
|
|
|
@ -264,12 +329,21 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
|
|
|
|
|
/**
|
|
|
|
|
* create trash folder
|
|
|
|
|
*/
|
|
|
|
|
// 创建“回收站”文件夹：最后，为回收站文件夹插入数据。
|
|
|
|
|
values.clear();
|
|
|
|
|
values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
|
|
|
|
|
values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
|
|
|
|
|
db.insert(TABLE.NOTE, null, values);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
//功能简介：
|
|
|
|
|
//创建data（数据）表
|
|
|
|
|
//解读：
|
|
|
|
|
//这个方法用于创建数据表，以及与之相关的触发器。
|
|
|
|
|
//创建数据表：使用db.execSQL方法执行预定义的SQL语句CREATE_DATA_TABLE_SQL，用于创建数据表。
|
|
|
|
|
//重新创建数据表触发器：调用reCreateDataTableTriggers方法，用于删除并重新创建与数据表相关的触发器。
|
|
|
|
|
//创建索引：使用db.execSQL方法执行CREATE_DATA_NOTE_ID_INDEX_SQL语句，为数据表创建索引。
|
|
|
|
|
//记录日志：使用Log.d方法记录一条调试级别的日志，表示数据表已经创建。
|
|
|
|
|
public void createDataTable(SQLiteDatabase db) {
|
|
|
|
|
db.execSQL(CREATE_DATA_TABLE_SQL);
|
|
|
|
|
reCreateDataTableTriggers(db);
|
|
|
|
|
@ -277,6 +351,10 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
|
|
|
|
|
Log.d(TAG, "data table has been created");
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
//和上面的note表的reCreate...同理
|
|
|
|
|
//重新创建或更新与笔记表相关的触发器。
|
|
|
|
|
//首先，使用DROP TRIGGER IF EXISTS语句删除已存在的触发器。确保在重新创建触发器之前，不存在同名的触发器。
|
|
|
|
|
//然后，使用db.execSQL()方法执行预定义的SQL语句，这些语句用于创建新的触发器。
|
|
|
|
|
private void reCreateDataTableTriggers(SQLiteDatabase db) {
|
|
|
|
|
db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_insert");
|
|
|
|
|
db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_update");
|
|
|
|
|
@ -287,6 +365,11 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
|
|
|
|
|
db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
//解读：
|
|
|
|
|
//synchronized关键字确保在多线程环境下，只有一个线程能够进入这个方法，防止了同时创建多个实例的情况
|
|
|
|
|
//getInstance(Context context)方法使用了单例模式来确保整个应用程序中只有一个NotesDatabaseHelper实例。
|
|
|
|
|
//它首先检查mInstance（类的静态成员变量，没有在代码片段中显示）是否为null。
|
|
|
|
|
//如果是null，则创建一个新的NotesDatabaseHelper实例，并将其赋值给mInstance。最后返回mInstance。
|
|
|
|
|
static synchronized NotesDatabaseHelper getInstance(Context context) {
|
|
|
|
|
if (mInstance == null) {
|
|
|
|
|
mInstance = new NotesDatabaseHelper(context);
|
|
|
|
|
@ -294,12 +377,19 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
|
|
|
|
|
return mInstance;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
//功能简介：
|
|
|
|
|
//当数据库首次创建时，onCreate方法会被调用。
|
|
|
|
|
//这里重写onCreate方法，它调用了上述createNoteTable(db)和createDataTable(db)两个方法
|
|
|
|
|
//这样首次创建数据库时就多出了两张表。
|
|
|
|
|
@Override
|
|
|
|
|
public void onCreate(SQLiteDatabase db) {
|
|
|
|
|
createNoteTable(db);
|
|
|
|
|
createDataTable(db);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
//功能简介：
|
|
|
|
|
//当数据库需要升级时（即数据库的版本号改变），onUpgrade方法会被调用。
|
|
|
|
|
//该方法会根据当前的oldVersion和新的newVersion来执行相应的升级操作
|
|
|
|
|
@Override
|
|
|
|
|
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
|
|
|
|
|
boolean reCreateTriggers = false;
|
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@ -327,12 +417,17 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
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reCreateDataTableTriggers(db);
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}
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if (oldVersion != newVersion) {
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if (oldVersion != newVersion) { //数据库升级失败，抛出一个异常，表示数据库升级失败
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throw new IllegalStateException("Upgrade notes database to version " + newVersion
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+ "fails");
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}
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}
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//功能简介：
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// 将数据库从版本1升级到版本2。
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//解读：
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// 首先，它删除了已经存在的NOTE和DATA表（如果存在的话）。DROP TABLE IF EXISTS语句确保了即使这些表不存在，也不会抛出错误。
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// 然后，它调用了createNoteTable(db)和createDataTable(db)方法来重新创建这两个表。这意味着在升级到版本2时，这两个表的内容会被完全清除，并重新创建新的空表。
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private void upgradeToV2(SQLiteDatabase db) {
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db.execSQL("DROP TABLE IF EXISTS " + TABLE.NOTE);
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db.execSQL("DROP TABLE IF EXISTS " + TABLE.DATA);
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@ -340,6 +435,12 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
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createDataTable(db);
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}
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//功能简介：
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// 将数据库从版本2（或可能是跳过版本2的某个状态）升级到版本3。
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//解读：
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// 首先，删除了三个不再使用的触发器（如果存在的话）。触发器是数据库中的一种对象，可以在插入、更新或删除记录时自动执行某些操作。
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// 然后，使用ALTER TABLE语句修改表结构，向NOTE表中添加了一个名为GTASK_ID的新列，并设置默认值为空字符串。
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// 最后，向NOTE表中插入了一条新的系统文件夹记录，表示一个名为“trash folder”的系统文件夹。这可能是用于存储已删除笔记的回收站功能。
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private void upgradeToV3(SQLiteDatabase db) {
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// drop unused triggers
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db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_insert");
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@ -355,8 +456,12 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
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db.insert(TABLE.NOTE, null, values);
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}
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//功能简介：
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// 这个方法负责将数据库从版本3升级到版本4。
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//解读：
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// 它向NOTE表中添加了一个名为VERSION的新列，并设置了默认值为0。这个新列用于记录标签版本信息。
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private void upgradeToV4(SQLiteDatabase db) {
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db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION
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+ " INTEGER NOT NULL DEFAULT 0");
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}
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}
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}
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Your Name
2 days ago
