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NotesDatabaseHelper注释

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ice
karlsilver 2 months ago
parent da72ad328d
commit 828603b9e9
1 changed files with 230 additions and 133 deletions
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java/net/micode/notes/data/NotesDatabaseHelper.java
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@ -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");
}
}
}
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