import java.util.Date;import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;public class DB {
private static final String DATABASE_NAME="notes.db";
private static final int DATABASE_VERSION=1;
private static final String DATABASE_TABLE="notes";
private static final String DATABASE_CREATE=
"create table notes("
+"_id INTEGER PRIMARY KEY,"
+"note TEXT NOT NULL,"
+"created INTEGER"
+");";
private static class DatabaseHelper extends SQLiteOpenHelper{ public DatabaseHelper(Context context) {
super(context,DATABASE_NAME, null, DATABASE_VERSION);
// TODO Auto-generated constructor stub
} @Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL(DATABASE_CREATE);
} @Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS "+DATABASE_TABLE); onCreate(db);
}
}
private Context mCtx=null;
private DatabaseHelper dbHelper;
private SQLiteDatabase db;
public DB(Context ctx){
this.mCtx=ctx;
}
public DB open() throws SQLException{
dbHelper=new DatabaseHelper(mCtx);
db=dbHelper.getWritableDatabase();
return this;
}
public void close(){
dbHelper.close();
}
public static final String KEY_ROWID="_id";
public static final String KEY_NOTE="note";
public static final String KEY_CREATED="created";
String[] strCols=new String[]{
KEY_ROWID,KEY_NOTE,KEY_CREATED
};
public Cursor getAll(){
return db.query(DATABASE_TABLE,strCols,null,null,null,null,null);
}
//增加记录
public long create(String Note){
Date now=new Date();
ContentValues args=new ContentValues();
args.put(KEY_NOTE, Note);
args.put(KEY_CREATED, now.getTime());
return db.insert(DATABASE_TABLE,null,args);
}
//删除记录
public boolean delete(long rowId){
return db.delete(DATABASE_TABLE, KEY_ROWID+"="+rowId,null )>0;
}
//查询单条记录
public Cursor get(long rowId) throws SQLException{
Cursor mCursor=db.query(true,
DATABASE_TABLE,
new String[]{KEY_ROWID,KEY_NOTE,KEY_CREATED},
KEY_ROWID+"=" +rowId,
null,null,null,null,null);
if(mCursor!=null){
mCursor.moveToFirst();
}
return mCursor;
}
//更新记录
public boolean update(long rowId,String note){
ContentValues args=new ContentValues();
args.put(KEY_NOTE, note);
return db.update(DATABASE_TABLE, args, KEY_ROWID+"="+rowId, null)>0;
}
}
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;public class DB {
private static final String DATABASE_NAME="notes.db";
private static final int DATABASE_VERSION=1;
private static final String DATABASE_TABLE="notes";
private static final String DATABASE_CREATE=
"create table notes("
+"_id INTEGER PRIMARY KEY,"
+"note TEXT NOT NULL,"
+"created INTEGER"
+");";
private static class DatabaseHelper extends SQLiteOpenHelper{ public DatabaseHelper(Context context) {
super(context,DATABASE_NAME, null, DATABASE_VERSION);
// TODO Auto-generated constructor stub
} @Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL(DATABASE_CREATE);
} @Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS "+DATABASE_TABLE); onCreate(db);
}
}
private Context mCtx=null;
private DatabaseHelper dbHelper;
private SQLiteDatabase db;
public DB(Context ctx){
this.mCtx=ctx;
}
public DB open() throws SQLException{
dbHelper=new DatabaseHelper(mCtx);
db=dbHelper.getWritableDatabase();
return this;
}
public void close(){
dbHelper.close();
}
public static final String KEY_ROWID="_id";
public static final String KEY_NOTE="note";
public static final String KEY_CREATED="created";
String[] strCols=new String[]{
KEY_ROWID,KEY_NOTE,KEY_CREATED
};
public Cursor getAll(){
return db.query(DATABASE_TABLE,strCols,null,null,null,null,null);
}
//增加记录
public long create(String Note){
Date now=new Date();
ContentValues args=new ContentValues();
args.put(KEY_NOTE, Note);
args.put(KEY_CREATED, now.getTime());
return db.insert(DATABASE_TABLE,null,args);
}
//删除记录
public boolean delete(long rowId){
return db.delete(DATABASE_TABLE, KEY_ROWID+"="+rowId,null )>0;
}
//查询单条记录
public Cursor get(long rowId) throws SQLException{
Cursor mCursor=db.query(true,
DATABASE_TABLE,
new String[]{KEY_ROWID,KEY_NOTE,KEY_CREATED},
KEY_ROWID+"=" +rowId,
null,null,null,null,null);
if(mCursor!=null){
mCursor.moveToFirst();
}
return mCursor;
}
//更新记录
public boolean update(long rowId,String note){
ContentValues args=new ContentValues();
args.put(KEY_NOTE, note);
return db.update(DATABASE_TABLE, args, KEY_ROWID+"="+rowId, null)>0;
}
}
import java.util.Date;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
//创造了一个类
public class DB {
//定义了一些私有的静态常量
//数据库的名字
private static final String DATABASE_NAME="notes.db";
//数据库的版本号
private static final int DATABASE_VERSION=1;
//表名
private static final String DATABASE_TABLE="notes";
//一个sql语句作用创造一个表 notes两个字段
private static final String DATABASE_CREATE=
"create table notes("
+"_id INTEGER PRIMARY KEY,"
+"note TEXT NOT NULL,"
+"created INTEGER"
+");";
//定义一个静态的类Databasehelper继承了SQLiteOpenHelper
private static class DatabaseHelper extends SQLiteOpenHelper{
//该类的构造方法
public DatabaseHelper(Context context) {
super(context,DATABASE_NAME, null, DATABASE_VERSION);
// TODO Auto-generated constructor stub
}
//当实例化这个类的时候将会调用该方法,该方法就会创建一个在数据库中创建一张表
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL(DATABASE_CREATE); }
//该方法是更新数据库
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
//他是这么做的如果这个表存在着删除它,然后在重新创建一个表
db.execSQL("DROP TABLE IF EXISTS "+DATABASE_TABLE); onCreate(db);
} }
//定义了一些成员变量
private Context mCtx=null;
private DatabaseHelper dbHelper;
private SQLiteDatabase db;
public DB(Context ctx){
this.mCtx=ctx;
}
//该方法返回一个可以读写的数据库的助手类对象
public DB open() throws SQLException{
dbHelper=new DatabaseHelper(mCtx);
db=dbHelper.getWritableDatabase();
return this;
}
//关闭数据库
public void close(){
dbHelper.close();
}
//定义一些全局静态常量
public static final String KEY_ROWID="_id";
public static final String KEY_NOTE="note";
public static final String KEY_CREATED="created";
String[] strCols=new String[]{
KEY_ROWID,KEY_NOTE,KEY_CREATED
};
//得到游标对象
public Cursor getAll(){
return db.query(DATABASE_TABLE,strCols,null,null,null,null,null);
}
//增加记录
public long create(String Note){
Date now=new Date();
ContentValues args=new ContentValues();
args.put(KEY_NOTE, Note);
args.put(KEY_CREATED, now.getTime());
return db.insert(DATABASE_TABLE,null,args);
}
//删除记录
public boolean delete(long rowId){
return db.delete(DATABASE_TABLE, KEY_ROWID+"="+rowId,null )>0;
}
//查询单条记录
public Cursor get(long rowId) throws SQLException{
Cursor mCursor=db.query(true,
DATABASE_TABLE,
new String[]{KEY_ROWID,KEY_NOTE,KEY_CREATED},
KEY_ROWID+"=" +rowId,
null,null,null,null,null);
if(mCursor!=null){
mCursor.moveToFirst();
}
return mCursor;
}
//更新记录
public boolean update(long rowId,String note){
ContentValues args=new ContentValues();
args.put(KEY_NOTE, note);
return db.update(DATABASE_TABLE, args, KEY_ROWID+"="+rowId, null)>0;
}
}