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添加注释

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zbq
abandon 3 months ago
parent a768687c52
commit 0a5f074a70
1 changed files with 118 additions and 43 deletions
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157
Notes-master/src/net/micode/notes/data/NotesDatabaseHelper.java
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@ -2,16 +2,11 @@
* Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* 您可以在遵守License的前提下使用本文件
* 具体License内容可查阅：http://www.apache.org/licenses/LICENSE-2.0
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* 软件按"原样"分发，不提供任何形式的明示或暗示的保证
* 详见License中关于权限和限制的具体条款
*/
package net.micode.notes.data;
@ -26,22 +21,35 @@ import net.micode.notes.data.Notes.DataColumns;
import net.micode.notes.data.Notes.DataConstants;
import net.micode.notes.data.Notes.NoteColumns;
/**
* 笔记应用的数据库辅助类
* 负责创建和管理SQLite数据库，包括表结构、索引、触发器
* 实现了数据库版本升级和数据迁移逻辑
*/
public class NotesDatabaseHelper extends SQLiteOpenHelper {
private static final String DB_NAME = "note.db";
private static final int DB_VERSION = 4;
// 数据库基本信息
private static final String DB_NAME = "note.db"; // 数据库文件名
private static final int DB_VERSION = 4; // 当前数据库版本号
/**
* 表名接口定义
* 包含应用使用的所有表名常量
*/
public interface TABLE {
public static final String NOTE = "note";
public static final String DATA = "data";
public static final String NOTE = "note"; // 笔记/文件夹表
public static final String DATA = "data"; // 笔记附属数据表
}
private static final String TAG = "NotesDatabaseHelper";
private static NotesDatabaseHelper mInstance; // 单例实例
private static NotesDatabaseHelper mInstance;
/**
* 笔记表创建SQL语句
* 定义了笔记和文件夹的存储结构，包含：
* - 基础信息字段（ID、父文件夹ID、创建时间等）
* - 提醒相关字段（提醒时间、背景颜色等）
* - 同步相关字段（同步ID、本地修改标识等）
*/
private static final String CREATE_NOTE_TABLE_SQL =
"CREATE TABLE " + TABLE.NOTE + "(" +
NoteColumns.ID + " INTEGER PRIMARY KEY," +
@ -52,17 +60,21 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
NoteColumns.HAS_ATTACHMENT + " INTEGER NOT NULL DEFAULT 0," +
NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
NoteColumns.NOTES_COUNT + " INTEGER NOT NULL DEFAULT 0," +
NoteColumns.SNIPPET + " TEXT NOT NULL DEFAULT ''," +
NoteColumns.SNIPPET + " TEXT NOT NULL DEFAULT '',' +
NoteColumns.TYPE + " INTEGER NOT NULL DEFAULT 0," +
NoteColumns.WIDGET_ID + " INTEGER NOT NULL DEFAULT 0," +
NoteColumns.WIDGET_TYPE + " INTEGER NOT NULL DEFAULT -1," +
NoteColumns.SYNC_ID + " INTEGER NOT NULL DEFAULT 0," +
NoteColumns.LOCAL_MODIFIED + " INTEGER NOT NULL DEFAULT 0," +
NoteColumns.ORIGIN_PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT ''," +
NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT '',' +
NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0" +
")";
/**
* 附属数据表创建SQL语句
* 存储笔记的详细内容和扩展数据，通过NOTE_ID关联到note表
*/
private static final String CREATE_DATA_TABLE_SQL =
"CREATE TABLE " + TABLE.DATA + "(" +
DataColumns.ID + " INTEGER PRIMARY KEY," +
@ -70,20 +82,22 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
DataColumns.NOTE_ID + " INTEGER NOT NULL DEFAULT 0," +
NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
DataColumns.CONTENT + " TEXT NOT NULL DEFAULT ''," +
DataColumns.CONTENT + " TEXT NOT NULL DEFAULT '',' +
DataColumns.DATA1 + " INTEGER," +
DataColumns.DATA2 + " INTEGER," +
DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," +
DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," +
DataColumns.DATA3 + " TEXT NOT NULL DEFAULT '',' +
DataColumns.DATA4 + " TEXT NOT NULL DEFAULT '',' +
DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" +
")";
// 为DATA表的NOTE_ID创建索引，提高查询效率
private static final String CREATE_DATA_NOTE_ID_INDEX_SQL =
"CREATE INDEX IF NOT EXISTS note_id_index ON " +
TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";
/**
* Increase folder's note count when move note to the folder
* 文件夹笔记数量更新触发器（更新时增加计数）
* 当笔记的父文件夹ID更新时，增加目标文件夹的笔记数量
*/
private static final String NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
"CREATE TRIGGER increase_folder_count_on_update "+
@ -95,7 +109,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" END";
/**
* Decrease folder's note count when move note from folder
* 文件夹笔记数量更新触发器（更新时减少计数）
* 当笔记的父文件夹ID更新时，减少原文件夹的笔记数量
*/
private static final String NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
"CREATE TRIGGER decrease_folder_count_on_update " +
@ -108,7 +123,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" END";
/**
* Increase folder's note count when insert new note to the folder
* 文件夹笔记数量插入触发器
* 当新笔记插入时，增加目标文件夹的笔记数量
*/
private static final String NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER =
"CREATE TRIGGER increase_folder_count_on_insert " +
@ -120,7 +136,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" END";
/**
* Decrease folder's note count when delete note from the folder
* 文件夹笔记数量删除触发器
* 当笔记删除时，减少原文件夹的笔记数量
*/
private static final String NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER =
"CREATE TRIGGER decrease_folder_count_on_delete " +
@ -133,7 +150,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" END";
/**
* Update note's content when insert data with type {@link DataConstants#NOTE}
* 笔记内容更新触发器（插入数据时）
* 当插入文本笔记类型的数据时，更新对应笔记的摘要内容
*/
private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER =
"CREATE TRIGGER update_note_content_on_insert " +
@ -146,7 +164,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" END";
/**
* Update note's content when data with {@link DataConstants#NOTE} type has changed
* 笔记内容更新触发器（更新数据时）
* 当文本笔记类型的数据更新时，更新对应笔记的摘要内容
*/
private static final String DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER =
"CREATE TRIGGER update_note_content_on_update " +
@ -159,7 +178,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" END";
/**
* Update note's content when data with {@link DataConstants#NOTE} type has deleted
* 笔记内容更新触发器（删除数据时）
* 当文本笔记类型的数据删除时，清空对应笔记的摘要内容
*/
private static final String DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER =
"CREATE TRIGGER update_note_content_on_delete " +
@ -172,7 +192,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" END";
/**
* Delete datas belong to note which has been deleted
* 笔记删除时关联数据删除触发器
* 当笔记删除时，删除其关联的所有附属数据
*/
private static final String NOTE_DELETE_DATA_ON_DELETE_TRIGGER =
"CREATE TRIGGER delete_data_on_delete " +
@ -183,7 +204,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" END";
/**
* Delete notes belong to folder which has been deleted
* 文件夹删除时子笔记删除触发器
* 当文件夹删除时，删除其包含的所有子笔记
*/
private static final String FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER =
"CREATE TRIGGER folder_delete_notes_on_delete " +
@ -194,7 +216,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" END";
/**
* Move notes belong to folder which has been moved to trash folder
* 文件夹移动到回收站时子笔记移动触发器
* 当文件夹移动到回收站时，将其子笔记也移动到回收站
*/
private static final String FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER =
"CREATE TRIGGER folder_move_notes_on_trash " +
@ -206,10 +229,15 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
" END";
// 构造函数，调用父类SQLiteOpenHelper的构造方法
public NotesDatabaseHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
/**
* 创建笔记表
* 执行表创建SQL，重建触发器，并创建系统文件夹
*/
public void createNoteTable(SQLiteDatabase db) {
db.execSQL(CREATE_NOTE_TABLE_SQL);
reCreateNoteTableTriggers(db);
@ -217,6 +245,10 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
Log.d(TAG, "note table has been created");
}
/**
* 重建笔记表相关触发器
* 先删除旧触发器再创建新触发器，确保触发器逻辑正确
*/
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");
@ -235,18 +267,22 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
db.execSQL(FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER);
}
/**
* 创建系统文件夹
* 初始化数据库时创建根文件夹、临时文件夹等系统必需文件夹
*/
private void createSystemFolder(SQLiteDatabase db) {
ContentValues values = new ContentValues();
/**
* call record foler for call notes
* 通话记录文件夹，用于存储通话笔记
*/
values.put(NoteColumns.ID, Notes.ID_CALL_RECORD_FOLDER);
values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
db.insert(TABLE.NOTE, null, values);
/**
* root folder which is default folder
* 根文件夹，默认文件夹
*/
values.clear();
values.put(NoteColumns.ID, Notes.ID_ROOT_FOLDER);
@ -254,7 +290,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
db.insert(TABLE.NOTE, null, values);
/**
* temporary folder which is used for moving note
* 临时文件夹，用于移动笔记时使用
*/
values.clear();
values.put(NoteColumns.ID, Notes.ID_TEMPARAY_FOLDER);
@ -262,7 +298,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
db.insert(TABLE.NOTE, null, values);
/**
* create trash folder
* 回收站文件夹
*/
values.clear();
values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
@ -270,6 +306,10 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
db.insert(TABLE.NOTE, null, values);
}
/**
* 创建附属数据表
* 执行表创建SQL，重建触发器，并创建索引
*/
public void createDataTable(SQLiteDatabase db) {
db.execSQL(CREATE_DATA_TABLE_SQL);
reCreateDataTableTriggers(db);
@ -277,6 +317,10 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
Log.d(TAG, "data table has been created");
}
/**
* 重建附属数据表相关触发器
* 先删除旧触发器再创建新触发器，确保触发器逻辑正确
*/
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 +331,10 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER);
}
/**
* 获取单例实例
* 提供线程安全的单例数据库帮助类实例获取方法
*/
static synchronized NotesDatabaseHelper getInstance(Context context) {
if (mInstance == null) {
mInstance = new NotesDatabaseHelper(context);
@ -294,45 +342,62 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
return mInstance;
}
/**
* 数据库创建回调
* 首次创建数据库时调用，创建所有表和初始化数据
*/
@Override
public void onCreate(SQLiteDatabase db) {
createNoteTable(db);
createDataTable(db);
}
/**
* 数据库版本升级回调
* 当数据库版本变化时调用，处理数据迁移逻辑
*/
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
boolean reCreateTriggers = false;
boolean skipV2 = false;
// 从版本1升级到版本2
if (oldVersion == 1) {
upgradeToV2(db);
skipV2 = true; // this upgrade including the upgrade from v2 to v3
skipV2 = true; // 此升级包含了从v2到v3的升级
oldVersion++;
}
// 从版本2升级到版本3
if (oldVersion == 2 && !skipV2) {
upgradeToV3(db);
reCreateTriggers = true;
oldVersion++;
}
// 从版本3升级到版本4
if (oldVersion == 3) {
upgradeToV4(db);
oldVersion++;
}
// 必要时重建触发器
if (reCreateTriggers) {
reCreateNoteTableTriggers(db);
reCreateDataTableTriggers(db);
}
// 验证升级是否完成
if (oldVersion != newVersion) {
throw new IllegalStateException("Upgrade notes database to version " + newVersion
+ " fails");
}
}
/**
* 升级到版本2
* 重新创建表结构（相当于清空旧数据）
*/
private void upgradeToV2(SQLiteDatabase db) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE.NOTE);
db.execSQL("DROP TABLE IF EXISTS " + TABLE.DATA);
@ -340,21 +405,31 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
createDataTable(db);
}
/**
* 升级到版本3
* - 添加Google Tasks ID列
* - 添加回收站系统文件夹
* - 删除不再使用的触发器
*/
private void upgradeToV3(SQLiteDatabase db) {
// drop unused triggers
// 删除不再使用的触发器
db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_insert");
db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_delete");
db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_update");
// add a column for gtask id
// 添加Google Tasks ID列
db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.GTASK_ID
+ " TEXT NOT NULL DEFAULT ''");
// add a trash system folder
// 添加回收站系统文件夹
ContentValues values = new ContentValues();
values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
db.insert(TABLE.NOTE, null, values);
}
/**
* 升级到版本4
* 添加数据版本号列，用于冲突检测和数据同步
*/
private void upgradeToV4(SQLiteDatabase db) {
db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION
+ " INTEGER NOT NULL DEFAULT 0");

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