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Update NotesDatabaseHelper.java

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m49q7e6zo 2 years ago
parent 3f4b6eb693
commit 8ddb3d162f
1 changed files with 78 additions and 92 deletions
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170
notes/data/NotesDatabaseHelper.java
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@ -15,39 +15,33 @@
*/
package net.micode.notes.data;
import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.content.ContentValues;//就是用于保存一些数据（string boolean byte double float int long short ...）信息，这些信息可以被数据库操作时使用。
import android.content.Context;//加载和访问资源。（android中主要是这两个功能，但是这里具体不清楚）
import android.database.sqlite.SQLiteDatabase;//主要提供了对应于添加、删除、更新、查询的操作方法： insert()、delete()、update()和query()。配合content.values
import android.database.sqlite.SQLiteOpenHelper;//用来管理数据的创建和版本更新
import android.util.Log;
import net.micode.notes.data.Notes.DataColumns;
import net.micode.notes.data.Notes.DataConstants;
import net.micode.notes.data.Notes.NoteColumns;
//数据库操作，用SQLOpenhelper,对一些note和文件进行数据库的操作，比如删除文件后，将文件里的note也相应删除
public class NotesDatabaseHelper extends SQLiteOpenHelper {
//定义数据名称
private static final String DB_NAME = "note.db";
//定义数据库版本
private static final int DB_VERSION = 4;
//定义TABLE接口
public interface TABLE {
public interface TABLE { //接口，分成note和data，在后面的程序里分别使用过
public static final String NOTE = "note";
public static final String DATA = "data";
}
//定义标签
private static final String TAG = "NotesDatabaseHelper";
private static NotesDatabaseHelper mInstance;
//定义了SQL语句分别用于创建便签表、数据表、包含ID、便签和数据的表格
private static final String CREATE_NOTE_TABLE_SQL =
"CREATE TABLE " + TABLE.NOTE + "(" +
NoteColumns.ID + " INTEGER PRIMARY KEY," +
@ -67,9 +61,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
NoteColumns.ORIGIN_PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT ''," +
NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0" +
")";
//
")";//数据库中需要存储的项目的名称，就相当于创建一个表格的表头的内容。
private static final String CREATE_DATA_TABLE_SQL =
"CREATE TABLE " + TABLE.DATA + "(" +
DataColumns.ID + " INTEGER PRIMARY KEY," +
@ -83,16 +76,15 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," +
DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," +
DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" +
")";
")";//和上面的功能一样，主要是存储的项目不同
private static final String CREATE_DATA_NOTE_ID_INDEX_SQL =
"CREATE INDEX IF NOT EXISTS note_id_index ON " +
TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";
TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";//存储便签编号的一个数据表格
/**
* Increase folder's note count when move note to the folder
*/
//将笔记移动到文件夹时增加文件夹的笔记数
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 +
@ -100,12 +92,11 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" UPDATE " + TABLE.NOTE +
" SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
" WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
" END";
" END";//在文件夹中移入一个Note之后需要更改的数据的表格。
/**
* Decrease folder's note count when move note from folder
*/
//从文件夹中移动笔记时减少文件夹的笔记计数
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 +
@ -114,12 +105,11 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
" WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
" AND " + NoteColumns.NOTES_COUNT + ">0" + ";" +
" END";
" END";//在文件夹中移出一个Note之后需要更改的数据的表格。
/**
* Increase folder's note count when insert new note to the folder
*/
//在文件夹中插入新笔记时增加文件夹的笔记数
private static final String NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER =
"CREATE TRIGGER increase_folder_count_on_insert " +
" AFTER INSERT ON " + TABLE.NOTE +
@ -127,12 +117,11 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" UPDATE " + TABLE.NOTE +
" SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
" WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
" END";
" END";//在文件夹中插入一个Note之后需要更改的数据的表格。
/**
* Decrease folder's note count when delete note from the folder
*/
private static final String NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER =
"CREATE TRIGGER decrease_folder_count_on_delete " +
" AFTER DELETE ON " + TABLE.NOTE +
@ -141,12 +130,11 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
" WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
" AND " + NoteColumns.NOTES_COUNT + ">0;" +
" END";
" END";//在文件夹中删除一个Note之后需要更改的数据的表格。
/**
* Update note's content when insert data with type {@link DataConstants#NOTE}
*/
//插入类型为｛DataConstants.Note｝的数据时更新注释的内容
private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER =
"CREATE TRIGGER update_note_content_on_insert " +
" AFTER INSERT ON " + TABLE.DATA +
@ -155,12 +143,11 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" UPDATE " + TABLE.NOTE +
" SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
" WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
" END";
" END";//在文件夹中对一个Note导入新的数据之后需要更改的数据的表格。
/**
* Update note's content when data with {@link DataConstants#NOTE} type has changed
*/
//当｛DataConstants.Note｝类型的数据发生更改时，更新注释的内容
private static final String DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER =
"CREATE TRIGGER update_note_content_on_update " +
" AFTER UPDATE ON " + TABLE.DATA +
@ -169,12 +156,11 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" UPDATE " + TABLE.NOTE +
" SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
" WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
" END";
" END";//Note数据被修改后需要更改的数据的表格。
/**
* Update note's content when data with {@link DataConstants#NOTE} type has deleted
*/
//删除｛DataConstants.Note｝类型的数据后，更新注释的内容
private static final String DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER =
"CREATE TRIGGER update_note_content_on_delete " +
" AFTER delete ON " + TABLE.DATA +
@ -183,36 +169,33 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" UPDATE " + TABLE.NOTE +
" SET " + NoteColumns.SNIPPET + "=''" +
" WHERE " + NoteColumns.ID + "=old." + DataColumns.NOTE_ID + ";" +
" END";
" END";//Note数据被删除后需要更改的数据的表格。
/**
* Delete datas belong to note which has been deleted
*/
//删除数据属于已删除的注释
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";
" END";//删除已删除的便签的数据后需要更改的数据的表格。
/**
* Delete notes belong to folder which has been deleted
*/
//删除笔记属于已删除的文件夹
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";
" END";//删除已删除的文件夹的便签后需要更改的数据的表格。
/**
* Move notes belong to folder which has been moved to trash folder
*/
//移动笔记属于已移动到垃圾文件夹的文件夹
private static final String FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER =
"CREATE TRIGGER folder_move_notes_on_trash " +
" AFTER UPDATE ON " + TABLE.NOTE +
@ -221,19 +204,19 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" UPDATE " + TABLE.NOTE +
" SET " + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
" WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
" END";
" END";//还原垃圾桶中便签后需要更改的数据的表格。
public NotesDatabaseHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
}//构造函数，传入数据库的名称和版本
public void createNoteTable(SQLiteDatabase db) {
db.execSQL(CREATE_NOTE_TABLE_SQL);
reCreateNoteTableTriggers(db);
createSystemFolder(db);
Log.d(TAG, "note table has been created");
}
}//创建表格（用来存储标签属性）
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");
@ -242,7 +225,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_insert");
db.execSQL("DROP TRIGGER IF EXISTS folder_delete_notes_on_delete");
db.execSQL("DROP TRIGGER IF EXISTS folder_move_notes_on_trash");
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);
@ -250,18 +233,19 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER);
db.execSQL(FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER);
db.execSQL(FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER);
}
}//execSQL是数据库操作的API，主要是更改行为的SQL语句。
//在这里主要是用来重新创建上述定义的表格用的，先删除原来有的数据库的触发器再重新创建新的数据库
private void createSystemFolder(SQLiteDatabase db) {
ContentValues values = new ContentValues();
/**
* call record foler for call notes
*/
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
*/
@ -269,7 +253,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
values.put(NoteColumns.ID, Notes.ID_ROOT_FOLDER);
values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
db.insert(TABLE.NOTE, null, values);
/**
* temporary folder which is used for moving note
*/
@ -277,7 +261,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
values.put(NoteColumns.ID, Notes.ID_TEMPARAY_FOLDER);
values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
db.insert(TABLE.NOTE, null, values);
/**
* create trash folder
*/
@ -285,78 +269,80 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
db.insert(TABLE.NOTE, null, values);
}
}//创建几个系统文件夹
public void createDataTable(SQLiteDatabase db) {
db.execSQL(CREATE_DATA_TABLE_SQL);
reCreateDataTableTriggers(db);
db.execSQL(CREATE_DATA_NOTE_ID_INDEX_SQL);
Log.d(TAG, "data table has been created");
}
}//创建表格（用来存储标签内容）
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");
db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_delete");
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);
}
}//同上面的execSQL
static synchronized NotesDatabaseHelper getInstance(Context context) {
if (mInstance == null) {
mInstance = new NotesDatabaseHelper(context);
}
return mInstance;
}
}//上网查是为解决同一时刻只能有一个线程执行.
//在写程序库代码时，有时有一个类需要被所有的其它类使用，
//但又要求这个类只能被实例化一次，是个服务类，定义一次，其它类使用同一个这个类的实例
@Override
public void onCreate(SQLiteDatabase db) {
createNoteTable(db);
createDataTable(db);
}
}//实现两个表格（上面创建的两个表格）
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
boolean reCreateTriggers = false;
boolean skipV2 = false;
if (oldVersion == 1) {
upgradeToV2(db);
skipV2 = true; // this upgrade including the upgrade from v2 to v3
oldVersion++;
}
if (oldVersion == 2 && !skipV2) {
upgradeToV3(db);
reCreateTriggers = true;
oldVersion++;
}
if (oldVersion == 3) {
upgradeToV4(db);
oldVersion++;
}
if (reCreateTriggers) {
reCreateNoteTableTriggers(db);
reCreateDataTableTriggers(db);
}
if (oldVersion != newVersion) {
throw new IllegalStateException("Upgrade notes database to version " + newVersion
+ "fails");
}
}
}//数据库版本的更新（数据库内容的更改）
private void upgradeToV2(SQLiteDatabase db) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE.NOTE);
db.execSQL("DROP TABLE IF EXISTS " + TABLE.DATA);
createNoteTable(db);
createDataTable(db);
}
}//更新到V2版本
private void upgradeToV3(SQLiteDatabase db) {
// drop unused triggers
db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_insert");
@ -370,10 +356,10 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
db.insert(TABLE.NOTE, null, values);
}
}//更新到V3版本
private void upgradeToV4(SQLiteDatabase db) {
db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION
+ " INTEGER NOT NULL DEFAULT 0");
}
}//更新到V4版本,但是不知道V2、V3、V4是什么意思
}

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