diff --git a/java/net/micode/notes/data/NotesDatabaseHelper.java b/java/net/micode/notes/data/NotesDatabaseHelper.java index ffe5d57..e035f21 100644 --- a/java/net/micode/notes/data/NotesDatabaseHelper.java +++ b/java/net/micode/notes/data/NotesDatabaseHelper.java @@ -26,198 +26,230 @@ import net.micode.notes.data.Notes.DataColumns; import net.micode.notes.data.Notes.DataConstants; import net.micode.notes.data.Notes.NoteColumns; - +/** + * 该类用于管理便签数据库的创建、升级和表结构维护。 + * 它继承自SQLiteOpenHelper，提供了创建便签表和数据记录表的方法，以及处理数据库版本升级的逻辑。 + */ public class NotesDatabaseHelper extends SQLiteOpenHelper { + // 数据库文件名 private static final String DB_NAME = "note.db"; - + // 数据库版本号 private static final int DB_VERSION = 4; + /** + * 定义数据库表名的接口 + */ public interface TABLE { + // 便签表名 public static final String NOTE = "note"; - + // 数据记录表名 public static final String DATA = "data"; } + // 日志标签，方便调试和日志记录 private static final String TAG = "NotesDatabaseHelper"; - + // 单例实例 private static NotesDatabaseHelper mInstance; + // 创建便签表的SQL语句 private static final String CREATE_NOTE_TABLE_SQL = - "CREATE TABLE " + TABLE.NOTE + "(" + - NoteColumns.ID + " INTEGER PRIMARY KEY," + - NoteColumns.PARENT_ID + " INTEGER NOT NULL DEFAULT 0," + - NoteColumns.ALERTED_DATE + " INTEGER NOT NULL DEFAULT 0," + - NoteColumns.BG_COLOR_ID + " INTEGER NOT NULL DEFAULT 0," + - NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," + - 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.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.VERSION + " INTEGER NOT NULL DEFAULT 0" + - ")"; - + "CREATE TABLE " + TABLE.NOTE + "(" + + NoteColumns.ID + " INTEGER PRIMARY KEY," + + NoteColumns.PARENT_ID + " INTEGER NOT NULL DEFAULT 0," + + NoteColumns.ALERTED_DATE + " INTEGER NOT NULL DEFAULT 0," + + NoteColumns.BG_COLOR_ID + " INTEGER NOT NULL DEFAULT 0," + + NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," + + 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.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.VERSION + " INTEGER NOT NULL DEFAULT 0" + + ")"; + + // 创建数据记录表的SQL语句 private static final String CREATE_DATA_TABLE_SQL = - "CREATE TABLE " + TABLE.DATA + "(" + - DataColumns.ID + " INTEGER PRIMARY KEY," + - DataColumns.MIME_TYPE + " TEXT NOT NULL," + - 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.DATA1 + " INTEGER," + - DataColumns.DATA2 + " INTEGER," + - DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," + - DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," + - DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" + - ")"; - + "CREATE TABLE " + TABLE.DATA + "(" + + DataColumns.ID + " INTEGER PRIMARY KEY," + + DataColumns.MIME_TYPE + " TEXT NOT NULL," + + 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.DATA1 + " INTEGER," + + DataColumns.DATA2 + " INTEGER," + + DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," + + DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," + + DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" + + ")"; + + // 创建数据记录表中note_id索引的SQL语句 private static final String CREATE_DATA_NOTE_ID_INDEX_SQL = - "CREATE INDEX IF NOT EXISTS note_id_index ON " + - TABLE.DATA + "(" + DataColumns.NOTE_ID + ");"; + "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 + * 当便签移动到文件夹时，增加文件夹便签数量的触发器SQL语句 */ private static final String NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER = - "CREATE TRIGGER increase_folder_count_on_update "+ - " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE + - " BEGIN " + - " UPDATE " + TABLE.NOTE + - " SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" + - " WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" + - " END"; + "CREATE TRIGGER increase_folder_count_on_update " + + " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE + + " BEGIN " + + " UPDATE " + TABLE.NOTE + + " SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" + + " WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" + + " END"; /** - * Decrease folder's note count when move note from folder + * 当便签从文件夹移出时，减少文件夹便签数量的触发器SQL语句 */ private static final String NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER = - "CREATE TRIGGER decrease_folder_count_on_update " + - " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE + - " BEGIN " + - " UPDATE " + TABLE.NOTE + - " SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" + - " WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID + - " AND " + NoteColumns.NOTES_COUNT + ">0" + ";" + - " END"; + "CREATE TRIGGER decrease_folder_count_on_update " + + " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE + + " BEGIN " + + " UPDATE " + TABLE.NOTE + + " SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" + + " WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID + + " AND " + NoteColumns.NOTES_COUNT + ">0" + ";" + + " END"; /** - * Increase folder's note count when insert new note to the folder + * 当插入新便签到文件夹时，增加文件夹便签数量的触发器SQL语句 */ private static final String NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER = - "CREATE TRIGGER increase_folder_count_on_insert " + - " AFTER INSERT ON " + TABLE.NOTE + - " BEGIN " + - " UPDATE " + TABLE.NOTE + - " SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" + - " WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" + - " END"; + "CREATE TRIGGER increase_folder_count_on_insert " + + " AFTER INSERT ON " + TABLE.NOTE + + " BEGIN " + + " UPDATE " + TABLE.NOTE + + " SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" + + " WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" + + " END"; /** - * Decrease folder's note count when delete note from the folder + * 当从文件夹删除便签时，减少文件夹便签数量的触发器SQL语句 */ private static final String NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER = - "CREATE TRIGGER decrease_folder_count_on_delete " + - " AFTER DELETE ON " + TABLE.NOTE + - " BEGIN " + - " UPDATE " + TABLE.NOTE + - " SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" + - " WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID + - " AND " + NoteColumns.NOTES_COUNT + ">0;" + - " END"; + "CREATE TRIGGER decrease_folder_count_on_delete " + + " AFTER DELETE ON " + TABLE.NOTE + + " BEGIN " + + " UPDATE " + TABLE.NOTE + + " SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" + + " WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID + + " AND " + NoteColumns.NOTES_COUNT + ">0;" + + " END"; /** - * Update note's content when insert data with type {@link DataConstants#NOTE} + * 当插入类型为笔记的数据时，更新便签内容的触发器SQL语句 */ private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER = - "CREATE TRIGGER update_note_content_on_insert " + - " AFTER INSERT ON " + TABLE.DATA + - " 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"; + "CREATE TRIGGER update_note_content_on_insert " + + " AFTER INSERT ON " + TABLE.DATA + + " 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 + * 当类型为笔记的数据更新时，更新便签内容的触发器SQL语句 */ 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 + * 当类型为笔记的数据删除时，更新便签内容的触发器SQL语句 */ 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 + * 当删除便签时，删除该便签相关数据的触发器SQL语句 */ 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 + * 当删除文件夹时，删除该文件夹下所有便签的触发器SQL语句 */ 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 + * 当文件夹移动到回收站时，将该文件夹下所有便签移动到回收站的触发器SQL语句 */ 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"; + /** + * 构造函数，初始化数据库帮助类 + * + * @param context 上下文对象 + */ public NotesDatabaseHelper(Context context) { super(context, DB_NAME, null, DB_VERSION); } + /** + * 创建便签表，包括执行创建表的SQL语句、重新创建触发器和创建系统文件夹 + * + * @param db 数据库对象 + */ public void createNoteTable(SQLiteDatabase db) { + // 执行创建便签表的SQL语句 db.execSQL(CREATE_NOTE_TABLE_SQL); + // 重新创建便签表的触发器 reCreateNoteTableTriggers(db); + // 创建系统文件夹 createSystemFolder(db); + // 记录日志，表明便签表已创建 Log.d(TAG, "note table has been created"); } + /** + * 重新创建便签表的触发器，包括删除旧触发器并创建新触发器 + * + * @param db 数据库对象 + */ private void reCreateNoteTableTriggers(SQLiteDatabase db) { + // 删除旧的触发器 db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_update"); db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_update"); db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_delete"); @@ -226,6 +258,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { db.execSQL("DROP TRIGGER IF EXISTS folder_delete_notes_on_delete"); db.execSQL("DROP TRIGGER IF EXISTS folder_move_notes_on_trash"); + // 创建新的触发器 db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER); db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER); db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER); @@ -235,18 +268,23 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { db.execSQL(FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER); } + /** + * 创建系统文件夹，包括通话记录文件夹、根文件夹、临时文件夹和回收站文件夹 + * + * @param db 数据库对象 + */ private void createSystemFolder(SQLiteDatabase db) { ContentValues values = new ContentValues(); /** - * call record foler for call notes + * 通话记录文件夹，用于存储通话便签 */ 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 +292,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { db.insert(TABLE.NOTE, null, values); /** - * temporary folder which is used for moving note + * 临时文件夹，用于移动便签 */ values.clear(); values.put(NoteColumns.ID, Notes.ID_TEMPARAY_FOLDER); @@ -262,7 +300,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { db.insert(TABLE.NOTE, null, values); /** - * create trash folder + * 创建回收站文件夹 */ values.clear(); values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER); @@ -270,23 +308,45 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { db.insert(TABLE.NOTE, null, values); } + /** + * 创建数据记录表，包括执行创建表的SQL语句、重新创建触发器和创建索引 + * + * @param db 数据库对象 + */ public void createDataTable(SQLiteDatabase db) { + // 执行创建数据记录表的SQL语句 db.execSQL(CREATE_DATA_TABLE_SQL); + // 重新创建数据记录表的触发器 reCreateDataTableTriggers(db); + // 创建数据记录表中note_id的索引 db.execSQL(CREATE_DATA_NOTE_ID_INDEX_SQL); + // 记录日志，表明数据记录表已创建 Log.d(TAG, "data table has been created"); } + /** + * 重新创建数据记录表的触发器，包括删除旧触发器并创建新触发器 + * + * @param db 数据库对象 + */ private void reCreateDataTableTriggers(SQLiteDatabase db) { + // 删除旧的触发器 db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_insert"); db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_update"); db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_delete"); + // 创建新的触发器 db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER); db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER); db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER); } + /** + * 获取单例实例 + * + * @param context 上下文对象 + * @return NotesDatabaseHelper实例 + */ static synchronized NotesDatabaseHelper getInstance(Context context) { if (mInstance == null) { mInstance = new NotesDatabaseHelper(context); @@ -294,69 +354,106 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { return mInstance; } + /** + * 数据库创建时调用，创建便签表和数据记录表 + * + * @param db 数据库对象 + */ @Override public void onCreate(SQLiteDatabase db) { + // 创建便签表 createNoteTable(db); + // 创建数据记录表 createDataTable(db); } + /** + * 数据库版本升级时调用，根据旧版本号执行相应的升级操作 + * + * @param db 数据库对象 + * @param oldVersion 旧版本号 + * @param newVersion 新版本号 + */ @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { boolean reCreateTriggers = false; boolean skipV2 = false; if (oldVersion == 1) { + // 从版本1升级到版本2 upgradeToV2(db); - skipV2 = true; // this upgrade including the upgrade from v2 to v3 + skipV2 = true; // 此升级包含从版本2到版本3的升级 oldVersion++; } if (oldVersion == 2 && !skipV2) { + // 从版本2升级到版本3 upgradeToV3(db); reCreateTriggers = true; oldVersion++; } if (oldVersion == 3) { + // 从版本3升级到版本4 upgradeToV4(db); oldVersion++; } if (reCreateTriggers) { + // 重新创建便签表和数据记录表的触发器 reCreateNoteTableTriggers(db); reCreateDataTableTriggers(db); } if (oldVersion != newVersion) { + // 升级失败，抛出异常 throw new IllegalStateException("Upgrade notes database to version " + newVersion + "fails"); } } + /** + * 从版本1升级到版本2，删除旧表并重新创建便签表和数据记录表 + * + * @param db 数据库对象 + */ private void upgradeToV2(SQLiteDatabase db) { + // 删除旧的便签表和数据记录表 db.execSQL("DROP TABLE IF EXISTS " + TABLE.NOTE); db.execSQL("DROP TABLE IF EXISTS " + TABLE.DATA); + // 重新创建便签表和数据记录表 createNoteTable(db); createDataTable(db); } + /** + * 从版本2升级到版本3，删除无用的触发器，添加gtask_id列和回收站文件夹 + * + * @param db 数据库对象 + */ private void upgradeToV3(SQLiteDatabase db) { - // drop unused triggers + // 删除无用的触发器 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 + // 为便签表添加gtask_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); } + /** + * 从版本3升级到版本4，为便签表添加version列 + * + * @param db 数据库对象 + */ private void upgradeToV4(SQLiteDatabase db) { + // 为便签表添加version列 db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0"); } -} +} \ No newline at end of file