C＃ SQLite Database Locked exception

The phenomenon

There is no problem when querying , But in Insert It will be reported that the database is locked .

Cause analysis

Maybe the code is connected to the database somewhere , I forgot to close it .

terms of settlement

I haven't completely understood the principle , But according to the following writing method, it does solve the problem .

Somewhere , The connection is open . Get rid of OpenConnection and CloseConnection change ExecuteNonQuery This ：

using (SQLiteConnection c = new SQLiteConnection(ConnectionString))
{
    
    c.Open();
    using (SQLiteCommand cmd = new SQLiteCommand(sql, c))
    {
    
        cmd.ExecuteNonQuery();
    }
}

Besides , Change the way of reading data to ：

using (SQLiteConnection c = new SQLiteConnection(ConnectionString))
{
    
    c.Open();
    using (SQLiteCommand cmd = new SQLiteCommand(sql, c))
    {
    
        using (SQLiteDataReader rdr = cmd.ExecuteReader())
        {
    
            ...
        }
    }
}

Don't try to manage the connection pool yourself like here . First , It is much more complex than the code you write , But second , It's already in SQLiteConnection Inside the object . Last , If you don't use it using, You don't handle these objects correctly , You will eventually encounter problems like you see now .

Reference resources

https://stackoverflow.com/questions/17592671/sqlite-database-locked-exception