pa2ltb7y5
/
Notes-master
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Update NotesDatabaseHelper.java

Browse Source
pull/2/head
puavjn2x9 12 months ago
parent 1fa0c23723
commit 13d9adb01d
1 changed files with 33 additions and 34 deletions
Show Stats Download Patch File Download Diff File

65
src/net/micode/notes/data/NotesDatabaseHelper.java
Unescape View File

@ -16,23 +16,23 @@
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;//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。
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 {
private static final String DB_NAME = "note.db";
private static final int DB_VERSION = 4;
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";
@ -61,7 +61,7 @@ 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 + "(" +
@ -76,11 +76,11 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," +
DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," +
DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" +
")";
")";//数据库中需要存储的项目的名称，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
@ -92,7 +92,7 @@ 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
@ -105,7 +105,7 @@ 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
@ -117,7 +117,7 @@ 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
@ -130,7 +130,7 @@ 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}
@ -143,7 +143,7 @@ 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
@ -156,7 +156,7 @@ 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
@ -169,7 +169,7 @@ 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
@ -180,7 +180,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" 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
@ -191,7 +191,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
" 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
@ -204,18 +204,18 @@ 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");
@ -233,8 +233,8 @@ 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。
//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();
@ -268,14 +268,14 @@ 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");
@ -285,20 +285,19 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
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;
}
}//解决同一时刻只能有一个线程执行.
@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) {
@ -331,14 +330,14 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
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
@ -353,10 +352,10 @@ 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

Write Preview
Loading…
Cancel
Save