Error : android.database.sqlite.SQLiteException; near "student_name" ; syntax error (code 1) ; while compiling : CR

The following error occurs when I click on insert Button

*Error : android.database.sqlite.SQLiteException; near "student_name" ; syntax error (code 1) ; while compiling : CREATE TABLE IF NOT EXISTS studentTable ( _id TEXT PRIMARY KEY student_name TEXT NOT NULL student_rollno TEXT NOT NULL );*

Coding

DbActivity.java

package com.example.a;

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.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;


public class DbActivity  {
public static final String KEY_ID = "_id";
public static final String KEY_NAME = "student_name";
public static final String KEY_ROLLNO = "student_rollno";


private static final String DATABASE_NAME= "Studentdb";
private static final int DATABASE_VERSION  = 1;
private static final String  DATABASE_TABLE = "studentTable";

private DbHelper ourHelper;
private final Context ourContext;
private SQLiteDatabase ourDatabase;

class DbHelper extends SQLiteOpenHelper {

    public DbHelper(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("CREATE TABLE IF NOT EXISTS " + DATABASE_TABLE + " ( " + 
        KEY_ID + " TEXT PRIMARY KEY " +
        KEY_NAME + " TEXT NOT NULL , " + 
        KEY_ROLLNO + " TEXT NOT NULL );" 
        );
            }

    @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);
    }

}


public DbActivity(Context c) {
ourContext = c;
}

public DbActivity open() throws SQLException{
    ourHelper = new DbHelper(ourContext);
    ourDatabase = ourHelper.getWritableDatabase();
    return this;
}

public void close() {
    ourHelper.close();
}

public void createEntry(String name, String id, String rollno) {
    // TODO Auto-generated method stub
    ContentValues cv = new ContentValues();
    cv.put(KEY_ID, id);
    cv.put(KEY_NAME, name);
    cv.put(KEY_ROLLNO, rollno);
    ourDatabase.insert(DATABASE_TABLE, null, cv);
}

MainActivity.java

package com.example.a;

import com.example.a.DbActivity;
import com.example.a.R;
import com.example.a.NextActivity;
import com.example.a.MainActivity;

import android.os.Bundle;
import android.app.Activity;

import android.app.Dialog;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity implements OnClickListener {

Button sqlUpdate,sqlView,sqlInsert,sqlDelete,sqlNext,sqlBack;
  EditText sqlName,sqlRollno,sqlId;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    sqlDelete = (Button) findViewById(R.id.bSQLDelete);
    sqlUpdate = (Button) findViewById(R.id.bSQLUpdate);
    sqlView = (Button) findViewById(R.id.bSQLView);
    sqlInsert = (Button) findViewById(R.id.bSQLInsert);
    sqlNext = (Button) findViewById(R.id.bSQLNext);
    sqlBack = (Button) findViewById(R.id.bSQLBack);

    sqlName = (EditText) findViewById(R.id.etSQLName);
    sqlRollno = (EditText) findViewById(R.id.etSQLRollno);
    sqlId = (EditText) findViewById(R.id.etSQLId);



    sqlUpdate.setOnClickListener(this);
    sqlView.setOnClickListener(this);
    sqlInsert.setOnClickListener(this);
    sqlNext.setOnClickListener(this);
    sqlDelete.setOnClickListener(this);
    sqlBack.setOnClickListener(this);

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

@Override
public void onClick(View v) {
    switch (v.getId()) {

    case R.id.bSQLNext :

         Intent i = new Intent(this,NextActivity.class);
         startActivity(i);           
         break;

    case R.id.bSQLInsert :

        boolean diditwork = true;        
         try {
            String name = sqlName.getText().toString();
            String rollno = sqlRollno.getText().toString();
        //    long lrollno = Long.parseLong(rollno);

            String id = sqlRollno.getText().toString();
          //  long lid = Long.parseLong(id);


             DbActivity empty = new DbActivity(MainActivity.this);
             empty.open();
             empty.createEntry(id,name,rollno);
             empty.close();
        } catch (Exception e) {
            diditwork = false;
            Dialog d = new Dialog(this);
            String error = e.toString();
            d.setTitle("dang");
            TextView tv = new TextView(this);
            tv.setText(error);
            d.setContentView(tv);
            d.show();
        }finally {
            if(diditwork)
            {
            Dialog d = new Dialog(this);
            d.setTitle("hech ya");
            TextView tv = new TextView(this);
            tv.setText("success");
            d.setContentView(tv);
            d.show();
        }

    }