设置使用SQLite和放大器的_ID场; ContentProvider的Andr​​oid中 [英] Setting the _ID field using SQLite & ContentProvider in Android

问题描述

我想建立一个ContentProvider的Andr​​oid应用中保存有关房屋的信息。我希望能够设置_ID场是相同ID字段在我的外部数据库（程序将同步与此外部数据库的ContentProvider）。

这样做的原因是，所以我想能够引用ID，如：

 内容：//com.example.acme.propertyprovider/properties/23
 

，其中图23是在两个外部数据库和内部数据库相同的ID。

下面只是导致错误android.database.SQLException：无法插入行内容：//com.example.acme.propertyprovider/properties

  ContentValues​​值=新ContentValues​​（）;values​​.put（Properties._ID，23）;
values​​.put（Properties.COLUMN_NAME_ROAD，123样品物业）;
values​​.put（Properties.COLUMN_NAME_RENT，320）;。getContentResolver（）插入（Properties.CONTENT_URI，价值观）;
 

解决方案

您会更好设置在Android数据库中的外键从外部数据库保存ID。然后，你就不必担心买不同步的东西。由于_ID字段是自动递增，你会为自己要创建一个噩梦。

添加类似extHouse_id（或其他）。这是一个非常普遍的做法。

I'm trying to set up a ContentProvider in an Android app to hold information about houses. I'd like to be able to set the _ID field to be the same as the ID field in my external database (the program will sync the ContentProvider with this external database).

The reason for this is so I would like to be able to reference the ID like:

content://com.example.acme.propertyprovider/properties/23

where 23 is the same ID in both the external database and the internal database.

The following just causes the error "android.database.SQLException: Failed to insert row into content://com.example.acme.propertyprovider/properties

ContentValues values = new ContentValues();

values.put(Properties._ID, 23);
values.put(Properties.COLUMN_NAME_ROAD, "123 Sample Property");
values.put(Properties.COLUMN_NAME_RENT, 320);

getContentResolver().insert(Properties.CONTENT_URI, values);

解决方案

You'd be better off setting a foreign key in the Android database to hold the id from your external database. Then you don't have to worry about things getting out of sync. Since the _ID fields are auto-incrementing you'll be creating a nightmare for yourself.

Add something like extHouse_id (or whatever). That's a very common practice.

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