안드로이드 게시판 공지사항 DB연동이 안되서요

Question

package io.github.hidroh.calendar;

import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

import io.github.hidroh.calendar.R;

public class BoardActivity extends AppCompatActivity {
    private String dtTitle = "";
    private String dtPassword = "";
    private String dtText = "";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_board);

        final Intent intent = getIntent();
        final String id = intent.getStringExtra("password");

        final EditText etTitle  = (EditText) findViewById(R.id.et_title_board);
        final EditText etPassword = (EditText) findViewById(R.id.et_password_board);
        final EditText etText = (EditText) findViewById(R.id.et_text_board);

        SQLiteDatabase db = openOrCreateDatabase("board.db", MODE_PRIVATE, null);
        String sql = "select " +
                " _id, Title, writer, password, content " +
                "from board where _id = '" + id + "'";
        Cursor cursor = db.rawQuery(sql, null);

        if (cursor.moveToNext()) {
            etTitle.setText(cursor.getString(1));
            etPassword.setText(cursor.getString(2));
            etText.setText(cursor.getString(3));

            dtTitle = cursor.getString(1);
            dtPassword = cursor.getString(2);
            dtText = cursor.getString(3);
        }

        findViewById(R.id.activity_board).setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                String stretTitle = etTitle.getText().toString();
                String stretPassword = etPassword.getText().toString();
                String stretText = etText.getText().toString();
                SQLiteDatabase db = openOrCreateDatabase("board.db", MODE_PRIVATE, null);

                String sql = "update board set \n" +
                        "title= '" + stretTitle + "' ,\n" +
                        "password= '" + stretPassword + "' ,\n" +
                        "text= '" + stretText + "' ,\n" +
                        "where _id = " + "password";
                db.execSQL(sql);

                Intent intent = new Intent();
                setResult(RESULT_OK, intent);
                finish();
            }
        });
    }
}