file share error if Sql Compact 4 in windows application - sql-server

Question

I am sorry but I want a final answer about that.
First I used SQL compact 3.5 for long time and it take from me long time to make tables and it is work good per one user application but now I have customer who want to run my soft on 8 computer by local network so I said ok then I try to share data file .sdf on server and use it but I get an error I don't remember it so I am searched on the internet and I saw that I must update to SQL compact 4 so update it and after that I get this Stupid error
I can’t Believe that this data don't support this type of use and it take too long time to make tables and other things on SQL compact database and the my customer will not wait me so what is the Reason
My SQL statement is this:
dt = New SqlCeConnection("Data Source=" & dpaa & "\MoveData.sdf;Encrypt Database=True;Password=123cdswdaas;File Mode=Read Write;Persist Security Info=False")

Answer 1

I think that previous answer is slightly misleading - you are definitely able use SQL Server CE 4.0 with database file located on network share. In fact, I am using this functionality in one of my active projects right now. "File Mode=Exclusive" parameter is not necessary - exclusive mode is the only available mode in such case.
The major drawback of this approach is that only one client is able to read from or write to database file at a given time, due to exclusive locking of entire SDF file. But there a circumstances when it is not possible to have full-featured SQL server in your environment (domain policy etc.). In such case shared database file is the only solution available.

Answer 2

Accessing SQL Compact database .sdf file on a network share by multiple users is not supported. You should use SQL Server Express edition for this. There are also multiple posts on stackoverflow on this subject. The version 3.5 supports opening .sdf file exclusively from a network share but 4.0 does not. But no SQL CE version supports shared access of multiple network users to 1 .sdf file.
But upgrading your application to support both SQL Express and SQL Compact databases could be relatively easy task. It depends on how your application access data. For example using Entity Framework your queries could be generated depending on your actual database connection.
You can also use generic classes DbConnection, DbCommand etc. instead of SqlCeConnection, SqlCeCommand etc. - thus you can change used database type without having to maintain two separate versions of your project.
Download SQL Express 2014 with Tools SQLEXPRWT http://msdn.microsoft.com/cs-cz/evalcenter/dn434042.aspx. (You can eventually use also older versions e.g. 2008) SQL Server has a lot more SQL features and data types than SQL CE, so watch that you use only stuff that is compatible with SQL CE.
In your app.config have you can have two connection strings:
<add name="CompactDBConnection" connectionString="data source=|DataDirectory|\CE.sdf; password=xxxxxx; SSCE:Max Buffer Size=16384; temp file max size=256; ssce:autoshrink threshold=100; ssce:max database size=4091" providerName="System.Data.SqlServerCe.4.0" />
<add name="ExpressDBConnection" connectionString="Server=myServerName\myInstanceName;Database=myDataBase;User Id=myUsername; Password=myPassword;" providerName="System.Data.SqlClient" />
You can chose then which one to use at the app startup
For creating DbConnection check this C# Retrieving correct DbConnection object by connection string.
Here is a small example of calling stored procedure using DbCommand instead of SqlCeCommand:
DbConnection dbConn = GetConnection(connStr);
DbProviderFactory sqlF = DbProviderFactories.GetFactory(dbConn);
using (DbCommand b2bcmd = sqlF.CreateCommand())
{
DbParameter msg = sqlF.CreateParameter();
msg.ParameterName = "#errorMessage";
msg.Direction = ParameterDirection.Output;
msg.DbType = DbType.String;
msg.Value = string.Empty;
msg.Size = 2048;
b2bcmd.Connection = dbConn;
b2bcmd.CommandType = CommandType.StoredProcedure;
b2bcmd.CommandText = "PB2BImport";
b2bcmd.Parameters.Add(msg);
b2bcmd.ExecuteNonQuery();
result = Convert.IsDBNull(msg.Value) ? "N/A" : (string)msg.Value;
}
I presume you do not use Entity framework - but it would be much easier with it.