正确的语法从一个表行复制到另一个（sqlite的机器人） [英] correct syntax to copy from one table row to another (sqlite android)

问题描述

请，这是复制从一个表中的特定行到另一个正确的语法？

please, is this the correct syntax for copying a particular row from one table to another?

db.execSQL("insert into Route select * from " + DATABASE_TABLE + " WHERE _id = rowId");

因为某种原因，当我调用执行该语句的方法，一切从第一个表中的项目被复制到第二个表，而不是特定行我想要的。谢谢。

because for some reason, when i call the method that executes this statement, all the items from the first table are copied into the second table and not the specific row i want. thanks.

这是方法调用的复制：

public void copyData(long rowId){
db.execSQL("insert into Route select * from " + DATABASE_TABLE + " WHERE _id = rowId"); 
}

如果没有

，请你告诉我怎么样？..

if not, could you please show me how?..

推荐答案

我看到一对夫妇的问题：

I see a couple of problems:

首先，你没有通过 ROWID 参数传送给了CopyData（）方法为部分查询时，您使用的字符串 ROWID 。

First, you're not passing the rowId argument to your copyData() method in as part of the query, you're using the string literal rowID.

二， ROWID 具有特殊的意义 SQLite中。这是一个伪列唯一标识表的每一行，通常是被分配到 INTEGER PRIMARY KEY 列，这是我猜相同的值是如何你有 _id 声明。其结果是，当 WHERE _id = ROWID 进行评估时，这两个值总是匹配，因此所有行被选中。

Second, ROWID has special meaning in SQLite. It's a pseudo-column that uniquely identifies each row in a table and is usually the same value that gets assigned to an INTEGER PRIMARY KEY column, which I'm guessing is how you have _id declared. The result is that when WHERE _id = ROWID is evaluated, the two values always match and therefore all rows are selected.

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