I am getting the following error..
//Cannot make static reference to non-static methos
//Cannot make static reference to non-static fields

I have use DBHelper as the object of DatabaseHelper class and db for SQLiteDatabase..
following is the code

package database.create;


import android.app.Activity;
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;
import android.util.Log;


public class DBAdapter extends Activity {

public static final String KEY_STDID = "_ID";
public static final String KEY_FNAMEID = "FNAME";
public static final String KEY_LNAMEID = "LNAME";
public static final String KEY_DOBID = "DOB";
public static final String KEY_HEIGHTID = "HEIGHT";
public static final String KEY_WEIGHTID = "WEIGHT";
private static final String TAG = "DBAdapter";

private static final String DATABASE_NAME = "HEALTHCARE";
private static final String DATABASE_TABLE = "PHYSICAL_FITNESS";
private static final int DATABASE_VERSION = 1;

public static final String DATABASE_CREATE = "create table PHYSICAL_FITNESS (_id integer primary key,"
+ "fname text not null, lname text not null," +
" d.o.b integer not null, height integer not null," + "weight integer not null); ";

private final Context context;
private DatabaseHelper DBHelper;
private SQLiteDatabase db;

public DBAdapter(Context ctx) {
this.context = ctx;
DBHelper = new DatabaseHelper(context);
}


private static class DatabaseHelper extends SQLiteOpenHelper
{
DatabaseHelper (Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

public void onCreate(SQLiteDatabase db)
{
db.execSQL(DATABASE_CREATE);
}
public void onUpgrade(SQLiteDatabase db, int oldVersion,
int newVersion)
{
Log.w(TAG, "Upgrading database from version " + oldVersion
+ " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS physical_fitness");
onCreate(db);

}

public DatabaseHelper open() throws SQLException
{
db = DBHelper.getWritableDatabase();
return this;
}

public void close()
{
DBHelper.close();
}
public long insertphysical_fitness (String _id, String FNAME, String LNAME, String DOB, String HEIGHT, String WEIGHT)
{
ContentValues initialvalues = new ContentValues();
initialvalues.put(KEY_STDID,_id);
initialvalues.put(KEY_FNAMEID, FNAME);
initialvalues.put(KEY_LNAMEID, LNAME);
initialvalues.put(KEY_DOBID, DOB);
initialvalues.put(KEY_HEIGHTID, HEIGHT);
initialvalues.put(KEY_WEIGHTID, WEIGHT);
return db.insert(DATABASE_TABLE, null, initialvalues);

}

public boolean deleteTitle(long rowID){
return db.delete(DATABASE_TABLE, KEY_STDID + "=" + rowID, null) > 0;

}
public Cursor getAllTitles()
{

return db.query(DATABASE_TABLE, new String[] {
KEY_STDID,
KEY_FNAMEID,
KEY_LNAMEID,
KEY_DOBID,
KEY_HEIGHTID,
KEY_WEIGHTID},
null,
null,
null,
null,
null);
}

//---retrieves a particular title---
public Cursor getTitle(long _Id) throws SQLException
{
Cursor mCursor =
db.query(true, DATABASE_TABLE, new String[] {
KEY_STDID,
KEY_FNAMEID,
KEY_LNAMEID,
KEY_DOBID,
KEY_HEIGHTID,
KEY_WEIGHTID
},
KEY_STDID + "=" + _Id,
null,
null,
null,
null,
null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}

//---updates a title---
public boolean updateTitle(long _Id, String FNAME,
String LNAME, String DOB, String HEIGHT, String WEIGHT)
{
ContentValues args = new ContentValues();
args.put(KEY_FNAMEID, FNAME);
args.put(KEY_LNAMEID, LNAME);
args.put(KEY_DOBID, DOB);
return db.update(DATABASE_TABLE, args,
KEY_STDID + "=" + _Id, null) > 0;
}
}
}