SQLiteHelper

/**
 * 实现对表的创建、更新、变更列名操作
 *
 *
 */
public class SQLiteHelper extends SQLiteOpenHelper {
    public static final String DB_NAME = "historyDB";
    public static final String TB_NAME = "historyTB";
    
    public SQLiteHelper(Context context)
    {
        super(context, DB_NAME, null, 1);
    }
    
    /**
     * 创建新表
     */
    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE IF NOT EXISTS " +
                TB_NAME + "(" +
                //HistoryBean.ID + " integer primary key," +
                HistoryBean.URL + " varchar," + 
                HistoryBean.TIME + " integer,"+
                HistoryBean.NAME + " varchar"+
                ")");
    }
    
    /**
     * 当检测与前一次创建数据库版本不一样时，先删除表再创建新表
     */
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TB_NAME);
        onCreate(db);
    }
    
    /**
     * 变更列名
     * @param db
     * @param oldColumn
     * @param newColumn
     * @param typeColumn
     */
    public void updateColumn(SQLiteDatabase db, String oldColumn, String newColumn, String typeColumn){
        try{
            db.execSQL("ALTER TABLE " +
                    TB_NAME + " CHANGE " +
                    oldColumn + " "+ newColumn +
                    " " + typeColumn
            );
        }catch(Exception e){
            e.printStackTrace();
        }
    }

}