如果检查表是否存在以保证连接打开SQLite中 [英] Checking if Table Exists Keeping Connection Open in SQLite

问题描述

所以我有一个方法，这是为了检查是否存在表中定义如下数据库：

So I have a method which is supposed to check if a table exists in a database which is defined as follows:

internal override bool TableExists(string tableName)
{
    bool tableExists = false;

    // Check the Tables schema and see if the table exists
    using (SQLiteConnection conn = (SQLiteConnection) CreateConnection())
    {
        conn.Open();
        DataRow[] rows = conn.GetSchema("Tables").Select(string.Format("Table_Name = '{0}'", tableName));
        tableExists = (rows.Length > 0);
    }

    // Actually called elsewhere in the code, just here for testing.
    File.Delete(DatabaseEnvironmentInfo.GetPrimaryDataFile(DatabaseName));

    return tableExists;
}

创建连接（）只是创建了一个连接字符串的新连接，所以我不认为这个问题是存在的。如果我有删除行 conn.GetSchema（表）... ，我能够删除数据库文件，但如果我添加该行早在我得到的当我尝试后删除以下异常的使用：

CreateConnection() just creates a new connection with a connection string so I don't think the issue is there. If I have remove the line conn.GetSchema("Tables")... and I am able to delete the database file but if I add that line back in I get the following exception when I try to delete after the using:

System.IO.IOException：进程   无法访问文件C：\ db.sqlite   因为它是正由另一个   流程。

System.IO.IOException: The process cannot access the file 'C:\db.sqlite' because it is being used by another process..

你的的DataRow 对象存到数据库的连接，或者没有人知道这个问题可能是什么？如果有更好的方法来检查，如果一个表中存在的SQLite我愿意接受这一点。

Do DataRowobjects keep a connection to the database or does anyone know what the issue could be? If there is a better way to check if a table exists in SQLite I am open to that as well.

谢谢！

推荐答案

好了，所以我已经想通了这个问题，所以我会张贴在这里万一有人遇到同样的问题。基本上我有连接池启用，因此连接是保持与数据库的开放式连接，这就是为什么我所看到的例外。刚过添加下面的使用：

Ok so I've figured out the issue so I'll post it here in case anyone comes across the same problem. Basically I had connection pooling enabled so the connections were maintaining an open connection with the database and that was why i was seeing the exception. Just add the following after the using:

SQLiteConnection.ClearAllPools();

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