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关于Android中内容操作数据库失败的原因及修改方法

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Jun 07, 2016 pm 02:50 PM

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最近学习Android开发，在Android Studio编写SQL语句。很熟悉的一点是，在Android Studio中写SQL语句的增删改查都是写在引号（）中的，因此在单词拼写错误的情况下，软件不会提示有错误，最近总结出了几点学习方法。 1.从Android Studio中导出所创建的数据

最近学习Android开发，在Android Studio编写SQL语句。

很熟悉的一点是，在Android Studio中写SQL语句的增删改查都是写在引号（" "）中的，因此在单词拼写错误的情况下，软件不会提示有错误，最近总结出了几点学习方法。

1.从Android Studio中导出所创建的数据库

在File Explorer下选择data文件夹，单击一下，在点击第二个data,在第二个data中寻找你所创建的文件夹

选择database文件下你所创建的数据库，然后导出到你的桌面或者别的地方

然后用MySql或者SQLite等可视化界面打开（DOS命令打开也可以），在这里我用MySql演示

contacts就是我所创建的数据库，内含两张表

将你代码中的SQL语句复制到该编辑区域，进行运行，检验是否有错误

（下图为错误提示，不同的错误会有不同的提示）

（下图为正确提示，正确提示会显示时间为多少秒）

SQL语句写的时候的注意事项：

1.注意你所写的内容在表格属性中是否存在；

2.在代码中注意问号的问号？

例如：

注意一下上面的两行代码，第一行是英文状态下的问号，第二行是中文状态下的问号，一定要重视这个问题，有时候语法全对，代码全对，但是程序无法按照指定的设置执行，可能就与这小小的问号有关。

语句中是不允许出现中文的？，而且中文的问号是无法被识别和操作的，既然无法识别和操作，这句语法是无法操作数据库的

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