android之数据库SQLite（一）

package com.example.myandroid;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class MyDatabaseHelper extends SQLiteOpenHelper{
	private static final String DATABASENAME = "mldn.db";
	private static final int DATABASEVERSION = 1;
	private static final String TABLENAME = "mytab";
	public MyDatabaseHelper(Context context){
		super(context,DATABASENAME,null,DATABASEVERSION);
	}
	public MyDatabaseHelper(MainActivity context) {
		super(context,DATABASENAME,null,DATABASEVERSION);
	}
	public void onCreate(SQLiteDatabase db){
		String sql = "CREATE TABLE "+TABLENAME+"("+
		"id			INTEGER			PRIMARY KEY,"+
		"name		VERCHAR(50)		NOT NULL,"+
		"birthday	DATE			NOT NULL)";
		db.execSQL(sql);
	}
	public void onUpgrade(SQLiteDatabase db,int oldVersion,int newVersion){
		String sql = "DROP TABLE IF EXITS "+TABLENAME;
		db.execSQL(sql);
		this.onCreate(db);
	}

}

package com.example.myandroid;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;
import java.util.Scanner;

import android.os.Bundle;
import android.app.Activity;
import android.content.SharedPreferences;
import android.database.sqlite.SQLiteOpenHelper;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.ExpandableListView.OnChildClickListener;
import android.widget.ExpandableListView.OnGroupClickListener;
import android.widget.ExpandableListView.OnGroupCollapseListener;
import android.widget.ExpandableListView.OnGroupExpandListener;
import android.widget.TabHost;
import android.widget.TabHost.TabSpec;
import android.widget.TextView;
import android.widget.Toast;


public class MainActivity extends Activity {
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        SQLiteOpenHelper helper =  new MyDatabaseHelper(this);
        helper.getWritableDatabase();
    }
   
}