如何在SQLiteDatabase辨别一个变种或Android的2瓦尔参数？ [英] How does the SQLiteDatabase to distinguish parameters for one var or two vars in android?

问题描述

有人告诉我：结果
在以下code时，参数2为变种numberType和参数5为变种的id

 光标光标= db.rawQuery（SELECT * FROM MYTABLE其中，numberType =和id =？，新的String [] {2，5}）;
 

在以下code，无论是参数6和参数4是用于变种标识。
我认为，code会导致错误，我认为新的String [] {6，4}必须在两个瓦尔匹配，对吧？

  db.delete（人，ID+=？，新的String [] {6，4}）;
 

我不能使用db.delete（...），以实现相同的功能，正如从test.db的删除其中id在（'6'，'4'） ！吧？

<一个href=\"http://stackoverflow.com/questions/19723403/how-can-pass-two-parameters-to-rawquery-in-android\">How可以在android系统传递两个参数rawQuery？结果
<一href=\"http://stackoverflow.com/questions/19701049/how-can-i-create-a-$c$c-if-i-need-to-delete-some-record-using-in-parameter-in-an\">How我可以创建一个code，如果我需要使用在Android的参数来删除一些记录？

解决方案

  

我觉得code会导致错误，我认为新的String [] {6，4}必须
  匹配两个瓦尔吧？

的简短的回答：的是。这件作品code将无法正常工作。

说明：

您要绑定两个参数 - 换句话说，你要替换两个占位符的 与bindArgs ¹ ？ （在你的案件数量6和4）。

在语句的参数数目要匹配的绑定到语句参数号 - 所以，如果你有三个参数查询（否则将引发异常）：

 从用户选择*其中id =？和年龄=？
 

您必须创建 whereArgs 字符串数组相同数量的参数（项）：

 的String [] = whereArgs {20345，18};
 

  

如何在SQLiteDatabase区分参数一个VAR或
  在Android的2瓦尔？

如上所述。对于你的情况正确的解决方案是：

• 添加第二个参数 WHERE 条款


• 从字符串数组中删除第二项

它可以是这样的：

  db.delete（人，ID =和引脚=？，新的String [] {6，4}）;
db.delete（人，ID =？，新的String [] {6}）;
db.delete（人，身份证件（？，）？，新的String [] {6，4}）;
 

结果
¹ _{更换为同样喜欢经典的Java：在查询的第一个参数将与第一项阵列等来代替}

Somebody told me:
In the following code, the parameter "2" is for var numberType and the parameter "5" is for var id

Cursor cursor = db.rawQuery("SELECT * FROM mytable where numberType=? and id=?", new String[] { "2","5" });

In the following code, both the parameter "6" and the parameter "4" are for var id. I think the code will cause error, I think new String[]{"6","4"} must match two vars, right?

db.delete("person", "id"+"=?", new String[]{"6","4"});

I can't use db.delete (...) to implement the same function just like delete from test.db where id in ('6','4')! right ?

How can pass two parameters to rawQuery in android?
How can I create a code if I need to delete some record using In parameter in android?

解决方案

I think the code will cause error, I think new String[]{"6","4"} must match two vars, right?

Short answer: Yes. This piece of code won't work.

Explanation:

You want to bind two parameters - in other words you want to replace two placeholders ? with bindArgs¹ (in your case number 6 and 4).

Number of parameters in statement have to match number of parameters binded to statement - so if you have three parameters in query (otherwise Exception will be thrown):

select * from Users where id = ? and age = ?

You have to create whereArgs string-array with same number of parameters (items):

String[] whereArgs = {"20345", "18"};

How does the SQLiteDatabase to distinguish parameters for one var or two vars in android?

Explained above. Correct solutions for your case are:

• add second parameter to WHERE clause
• remove second item from string-array

It can looks like:

db.delete("person", "id = ? and pin = ?", new String[] {"6", "4"});
db.delete("person", "id = ?", new String[] {"6"});
db.delete("person", "id in(?, ?)", new String[] {"6", "4"});

¹_{Replacing is same like in classic Java: first parameter in query will be replaced with first item in array etc.}

这篇关于如何在SQLiteDatabase辨别一个变种或Android的2瓦尔参数？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！