Android的SQLite的选择的args []为int值 [英] Android Sqlite selection args[] with int values

问题描述

在我DBHelper的getEvents方法，这行code。

Have this line of code in the getEvents method of my DBHelper.

    int year, month, day;
    String[] columns = new String[] { KEY_EVENTNAME, KEY_DESCRIPTION,
            KEY_HOUR, KEY_MINUTE, KEY_DAY, KEY_MONTH, KEY_YEAR,
            KEY_REMINDER };
    Cursor c = database.query(DATABASE_TABLE, columns, 
            KEY_YEAR + "=?"+ " AND " + KEY_MONTH + "=?" + " AND "+ KEY_DAY + "=?",
            new String[] {String.valueOf(year), String.valueOf(month), String.valueOf(day)}, 
            null, null, KEY_MONTH + " AND "
            + KEY_DAY);

它总是没有返回值。当我删除以下

It always returns nothing. When I remove the following

    int year, month, day;
    String[] columns = new String[] { KEY_EVENTNAME, KEY_DESCRIPTION,
            KEY_HOUR, KEY_MINUTE, KEY_DAY, KEY_MONTH, KEY_YEAR,
            KEY_REMINDER };
    Cursor c = database.query(DATABASE_TABLE, columns, 
            KEY_YEAR + "=?",
            new String[] {String.valueOf(year)}, 
            null, null, KEY_MONTH + " AND "
            + KEY_DAY);

运行正常。什么是与我的code中的问题？现在看来似乎不接受多个值where子句。 任何一个可以帮助我？谢谢你。

it runs correctly. What's the problem with my code? It seems like it doesn't accept multiple values as where clause. Can any one help me with this? Thanks.

推荐答案

答案是在标题：您想通过整数值到查询，但实际上你到底是什么了是的字符串值。

The answer is in the title: you are trying to pass integer values into the query, but what you actually end up with are string values.

这是Android数据库API中的一个可怕的设计缺陷;您可以使用参数仅供字符串。

This is a horrible design bug in the Android database API; you can use parameters only for strings.

整数数字不具有字符串值将有格式和SQL注入的问题，所以你可以直接插入数字到SQL EX pression：

Integer numbers do not have the formatting and SQL injection problems that string values would have, so you can just insert the numbers directly into the SQL expression:

Cursor c = database.query(
    DATABASE_TABLE, columns, 
    KEY_YEAR  + "=" + year  + " AND " +
    KEY_MONTH + "=" + month + " AND " +
    KEY_DAY   + "=" + day,
    null, null, null,
    KEY_MONTH + "," + KEY_DAY);

（和排序依据语法错了。）

这篇关于Android的SQLite的选择的args []为int值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！