以编程方式创建sqlite db（如果不存在）？ [英] Programmatically create sqlite db if it doesn't exist?

问题描述

我正在尝试以编程方式创建sqlite数据库（如果不存在）。我已经编写了以下代码，但在最后一行遇到了异常。

I am trying to create an sqlite db programmatically if it doesn't exist. I have written the following code but I am getting an exception at the last line.

if (!System.IO.File.Exists("C:\\Users\\abc\\Desktop\\1\\synccc.sqlite"))
{
    Console.WriteLine("Just entered to create Sync DB");
    SQLiteConnection.CreateFile("C:\\Users\\abc\\Desktop\\1\\synccc.sqlite");
    string sql = "create table highscores (name varchar(20), score int)";
    SQLiteCommand command = new SQLiteCommand(sql, sqlite2);
    command.ExecuteNonQuery();
}
sqlite2 = new SQLiteConnection("Data Source=C:\\Users\\abc\\Desktop\\1\\synccc.sqlite");

我在 command.ExecuteNonQuery（）;行得到了例外。异常为未处理无效的操作异常。还有其他方法可以将sqlite文件添加到您的项目中吗？我可以手动做吗？如果不是，那我该如何解决以上问题？

I get the exception at the line command.ExecuteNonQuery(); The exception is Invalid operation exception was unhandled. Is there any other way to add an sqlite file to your project? Can I do it manually? If not then how can I solve the above issue?

推荐答案

要在数据库上执行任何类型的数据定义命令，您需要打开连接以传递命令。在您的代码中，在执行查询之后创建连接。

To execute any kind of data definition command on the database you need an open connection to pass the command. In your code you create the connection AFTER the execution of the query.

当然，在创建之后，您需要打开连接

Of course, after that creation, you need to open the connection

if (!System.IO.File.Exists("C:\\Users\\abc\\Desktop\\1\\synccc.sqlite"))
{
    Console.WriteLine("Just entered to create Sync DB");
    SQLiteConnection.CreateFile("C:\\Users\\abc\\Desktop\\1\\synccc.sqlite");

    using(var sqlite2 = new SQLiteConnection("Data Source=C:\\Users\\abc\\Desktop\\1\\synccc.sqlite"))
    {
        sqlite2.Open();
        string sql = "create table highscores (name varchar(20), score int)";
        SQLiteCommand command = new SQLiteCommand(sql, sqlite2);
        command.ExecuteNonQuery();
    }
}

但是，如果您使用提供程序的版本3 ，则不必检查文件是否存在。只需打开连接即可创建该文件（如果不存在）。

However, if you use the version 3 of the provider, you don't have to check for the existence of the file. Just opening the connection will create the file if it doesn't exists.

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