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好,其他的岗位,我的意思是:如何组织类,同时使数据库应用程序使用SQLite
Should there be one SQLiteOpenHelper for each table in the database?
我是怀疑具有一种或应用更加助手,好了,anwser是1个帮手,很多专栏。
现在的第二部分,我其实做这个教程: http://www.vogella.com/articles/AndroidSQLite/article.html
,但我想通过在数据库上超过1台办呢,好吧,我所做的工作,现在我尝试创建所谓的数据访问对象“DAO”。问题是一样的,最好是有一个单独的DAO,或者最好每个表都有一个(每个表类都有一个),最后是一个单独的DAO类,其中包含所有可用于“操作”的DAO类应用程序...?
这是在本教程所谓DAO:
package de.vogella.android.sqlite.first;
import java.util.ArrayList;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
public class CommentsDataSource {
// Database fields
private SQLiteDatabase database;
private MySQLiteHelper dbHelper;
private String[] allColumns = { MySQLiteHelper.COLUMN_ID,
MySQLiteHelper.COLUMN_COMMENT };
public CommentsDataSource(Context context) {
dbHelper = new MySQLiteHelper(context);
}
public void open() throws SQLException {
database = dbHelper.getWritableDatabase();
}
public void close() {
dbHelper.close();
}
public Comment createComment(String comment) {
ContentValues values = new ContentValues();
values.put(MySQLiteHelper.COLUMN_COMMENT, comment);
long insertId = database.insert(MySQLiteHelper.TABLE_COMMENTS, null,
values);
Cursor cursor = database.query(MySQLiteHelper.TABLE_COMMENTS,
allColumns, MySQLiteHelper.COLUMN_ID + " = " + insertId, null,
null, null, null);
cursor.moveToFirst();
Comment newComment = cursorToComment(cursor);
cursor.close();
return newComment;
}
public void deleteComment(Comment comment) {
long id = comment.getId();
System.out.println("Comment deleted with id: " + id);
database.delete(MySQLiteHelper.TABLE_COMMENTS, MySQLiteHelper.COLUMN_ID
+ " = " + id, null);
}
public List<Comment> getAllComments() {
List<Comment> comments = new ArrayList<Comment>();
Cursor cursor = database.query(MySQLiteHelper.TABLE_COMMENTS,
allColumns, null, null, null, null, null);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
Comment comment = cursorToComment(cursor);
comments.add(comment);
cursor.moveToNext();
}
// Make sure to close the cursor
cursor.close();
return comments;
}
private Comment cursorToComment(Cursor cursor) {
Comment comment = new Comment();
comment.setId(cursor.getLong(0));
comment.setComment(cursor.getString(1));
return comment;
}
}
在此先感谢。
谢谢,你真是帮了我很多。 –