SQLite: Cannot open network file programmatically, even though worked before

问题

I have used the code below to open a SQLite database file that sits on a network computer for more than a year now almost on a daily basis. Suddenly this morning, I am not able to open the file programmatically.

private Boolean Connect(String strPathFile)
{
    // Initialize the connection object.
    this.DbConnection = null;

    try
    {
        // DATABASE: Create the connection string and set the settings.
        String strConnection = @"Data Source=" + strPathFile + @";Version=3;";

        // DATABASE: Connect to the database.
        this.DbConnection = new SQLiteConnection(strConnection);
        this.DbConnection.Open();

        return true;
    }

    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }

    return false;
}

The file is a network resource in the form "\Server\ShareName\FileName.db" (less the double quotes).

Here is the interesting thing. SQLite Administrator has no issues opening up the network database file, none, and repeatedly. I can also open up the file locally. I copied the file to my local drive and simply changed the path inside Visual Studio 2012 (VS2012).

The server seemed fine. It had gone through a reboot at some point since the last time that I checked on it. I presume a Microsoft Update. File Explorer has no issues browsing the folder, and as I said SQLite Administrator can open the network file.

I checked once again on permissions and everyone has full control as well as the server's users have full control, both on the security permissions and on the share permissions. I checked the folder and file, and permissions are the same. I expected as much, because SQLite Administrator can open the file. The server does not have a firewall set up, Windows Firewall or otherwise. I rechecked that this morning as well. Again, SQLite Administrator would have complained about that.

I verified writing, by making a copy of the file on the network drive using File Explorer. That had no issues.

The sever is a Windows Server 2003. I am using Windows 7 Professional 64-bit.

I also tried to open up the database in read only mode, but that failed as well. I was expecting that behavior. SQLite Administrator still works nicely.

I tried various other connection strings including SQLiteConnectionStringBuilder() just to see what happens, and all roads lead to Rome, namely:

System.Data.SQLite.SQLiteException occurred
  HResult=-2147467259
  Message=unable to open database file
  Source=System.Data.SQLite
  ErrorCode=14
  StackTrace:
       at System.Data.SQLite.SQLite3.Open(String strFilename, SQLiteConnectionFlags connectionFlags, SQLiteOpenFlagsEnum openFlags, Int32 maxPoolSize, Boolean usePool)
       at System.Data.SQLite.SQLiteConnection.Open()
       at SQL.cSQL.Connect(String strPathFile) in C:\<Path to source file>:line 367
  InnerException:

Thoughts?

回答1:

in version > 1.0.82.0

Double the leading two backslashes in the file name (e.g. "\\\\network\share\file.db").
Use a mapped drive letter.
Use the SQLiteConnection constructor that takes the parseViaFramework boolean argument and pass 'true' for that argument.

See the SQL post here

回答2:

I had a similar issue. Replacing the UNC (\server\share\folder\file.db) with a mapped drive path (S:\folder\file.db) resolve the issue in my instance.

回答3:

The error message is very misleading + irritating. Applications working fine in the local environment get failed to start in client server situation.

It has mostly noting to do with the code. Its related to server side.

Make sure the Write access is available for the server folder containing the file.
UNC [IP based server path] is not supported still, the network path/folder should be mapped to overcome this issue.
Some sites+users are saying to mention the Version No. in the connection string. All my applications are working fine without using it.

Connection String:

Data Source=[Mapped Server Location]\[SubFolders]\[FileName].db;

Update:

I tried to prepend \\ to the UNC path and it worked (added additional \\ in the beginning only, not in-between).

Data Source=\\[UNC]\[SubFolders]\[FileName].db;

来源：https://stackoverflow.com/questions/17303076/sqlite-cannot-open-network-file-programmatically-even-though-worked-before

标签

sqlite

visual-studio-2012

runtime-error