Android : สอบถามเรื่องการกำหนดเงื่อนไขก่อนจะทำการ Insert ข้อมูลลง SQLIte

package com.example.sqlitetest.helper;

public class DatabaseHelper extends SQLiteOpenHelper {

        private static final String DATABASE_NAME = "Timestamp";
	private static final int DATABASE_VERSION = 1;
	private static final String DATABASE_TABLE = "TimeRecord";
	
	private static final String COLUMN_AID = "aid";
	private static final String COLUMN_EMPLOYEEID = "employeeid";
	private static final String COLUMN_STATUS = "status";
	private static final String COLUMN_DATETIME = "createtime";
	
	private static final String DATABASE_CREATE = "create table "+ DATABASE_TABLE + "("
			+ COLUMN_AID + " INTEGER PRIMARY KEY AUTOINCREMENT," + COLUMN_EMPLOYEEID + " TEXT," 
			+ COLUMN_STATUS + " TEXT," + COLUMN_DATETIME + " DEFAULT CURRENT_TIMESTAMP)";
	
	public DatabaseHelper(Context context){
		super(context, DATABASE_NAME, null, DATABASE_VERSION);
	}

	@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);
	}

public void addTimeRecord(TimeRecord timerecord){
		SQLiteDatabase db = this.getWritableDatabase();
		ContentValues values = new ContentValues();
		values.put(COLUMN_EMPLOYEEID, timerecord.getEmployeeid());
		values.put(COLUMN_STATUS, timerecord.getStatus());
		values.put(COLUMN_DATETIME, getDateTime());
		
		db.insert(DATABASE_TABLE, null, values);
		db.close();
	}