使用insertWithOnConflict进行更新或插入 [英] Using insertWithOnConflict for update or insert

问题描述

我需要插入或更新，并且找到了SQLiteDatabase的方法insertWithOnConflict，但是我不知道它如何检查条目是否已经存在.

I need to insert or update and I found the method insertWithOnConflict of the SQLiteDatabase, but I do not know how it checks if the entry already exists.

从理论上讲，我需要一个"Where"参数来检查某个ID是否存在，如果存在，则应替换所有其他列.

Theoretically I need a "Where" argument to check if a certain ID exists, and if so, it should replace all other columns.

这就是我现在拥有的，但是我不认为第二个参数是唯一的ID

This is what I have now, but I don´t think that the second argument is the unique id

    ContentValues args = new ContentValues();
    args.put(AppDatabase.COLUMN_ID, entry.getId());
    args.put(AppDatabase.COLUMN_NAME, entry.getAppname());
    args.put(AppDatabase.COLUMN_URL, entry.getAppUrl());
    database.insertWithOnConflict(AppDatabase.TABLE_FILELIST, COLUMN_ID, args, SQLiteDatabase.CONFLICT_REPLACE);

我该如何管理这种行为?

How can I manage this behaviour?

推荐答案

1. 确保您的表中有一些适当的约束，例如PRIMARY KEY或UNIQUE.

插入时，通过ContentValues将一个值添加到此约束列中.如果插入新行会违反某些约束，则首先删除冲突的行，然后再插入新行.

When inserting, add a value to this constrained column via ContentValues. If inserting the new row would violate some constraint, the conflicting rows are first deleted and then the new row is inserted.

在您的情况下，COLUMN_ID看起来很适合PRIMARY KEY约束.无需在代码中使用值COLUMN_ID的第二个arg nullColumnHack，您可以将其作为null传递.

In your case, COLUMN_ID looks like a good candidate for PRIMARY KEY constraint. The second arg nullColumnHack with value COLUMN_ID in your code is not necessary, you can pass it as null.

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