1. Installing the .NET Framework 3.5 SP1 also installs the Visual C++ 2008 SP1 Runtime Libraries

2. Visual C++ 2008 SP1 Runtime Libraries can be downloaded and installed from the location given below:
   Visual C++ 2008

Note that installing .NET Framework 2.0 or .NET Framework 3.0 or .NET Framework 4 does not install the Visual C++ 2008 Runtime Libraries (x86 and x64), Service Pack 1.

If the SQL Server Compact Runtime installer is run on a machine which does not have a .Net Framework installed, the installation proceeds without any errors but there are a few steps which are not performed. It may cause errors on such a machine. The steps which are not performed are:

• The machine.config entry for .NET would not have entry for SQL Server Compact as a data provider.

• The relevant assemblies of Compact runtime are not put in the Global Assembly Cache.

This can also happen if a user performs the following steps:

• Install SQL Server Compact 4.0 runtime

• Install .NET Framework 3.5 SP1 or 4.0

To solve this problem, Reinstall / Repair SQL Server Compact runtime post .NET Framework installation.

SQL Server Compact 4.0 does not recognize the Encrypt property of the SqlCeConnection class, and you should not use this property to encrypt database files.

Use the Encryption Mode property of the SqlCeConnection class to encrypt SQL Server Compact 4.0 database files. The following examples show uses of the Encryption Mode property.

• To create a new encrypted SQL Server Compact 4.0 database:

  C#:

  SqlCeEngine engine = new SqlCeEngine("Data Source=Northwind.sdf;encryption mode=platform default;Password=<enterStrongPasswordHere>;"); engine.CreateDatabase();

  Visual Basic:

  Dim engine As SqlCeEngine = New SqlCeEngine("Data Source=Northwind.sdf;encryption mode=platform default;Password=<enterStrongPasswordHere>;") engine.CreateDatabase()

• To change the encryption mode of an existing SQL Server Compact 4.0 database:

  C#:

  SqlCeEngine engine = new SqlCeEngine("Data Source=Northwind.sdf;Password=<enterStrongPasswordHere>;"); engine.Compact("Data Source=Northwind.sdf;encryption mode= enginedefault;Password=<enterStrongPasswordHere>;");

  Visual Basic:

  Dim engine As SqlCeEngine = New SqlCeEngine("Data Source=Northwind.sdf;Password=<enterStrongPasswordHere>;") engine.Compact("Data Source=Northwind.sdf;encryption mode= engine default;Password=<enterStrongPasswordHere>;")

• To encrypt an unencrypted SQL Server Compact 4.0 database:

  C#:

  SqlCeEngine engine = new SqlCeEngine("Data Source=Northwind.sdf"); engine.Compact("Data Source=Northwind.sdf;encryption mode=platform default;Password=<enterStrongPasswordHere>;");

  Visual Basic:

  Dim engine As SqlCeEngine = New SqlCeEngine("Data Source=Northwind.sdf;") engine.Compact("Data Source=Northwind.sdf;encryption mode=platform default;Password=<enterStrongPasswordHere>;"

SQL Server Compact 4.0 data types for parameters like SqlDbType or DbType should be explicitly set.

If the data types for parameters such as SqlDbType or DbType are not explicitly set, an exception is be thrown. To resolve this issue, explicitly set the data type for parameters such as SqlDbType or DbType. This is critical in the case of BLOB data types (image and ntext). A code example is given below:

C#:

SqlCeEngine engine = new SqlCeEngine(connString);
engine.CreateDatabase();
engine.Dispose();

SqlCeConnection conn = new SqlCeConnection(connString);
conn.Open();

SqlCeCommand cmd = conn.CreateCommand();
cmd.CommandText = "CREATE TABLE BlobTable(name nvarchar(128), blob ntext);";
cmd.ExecuteNonQuery();

cmd.CommandText = "INSERT INTO BlobTable(name, blob) VALUES (@name, @blob);";
SqlCeParameter paramName = cmd.Parameters.Add("name", SqlDbType.NVarChar, 128);
SqlCeParameter paramBlob = cmd.Parameters.Add("blob", SqlDbType.NText);
paramName.Value = "Name1";
paramBlob.Value = "Name1".PadLeft(4001);

cmd.ExecuteNonQuery();

Visual Basic:

Dim engine As SqlCeEngine = New SqlCeEngine(connString)
engine.CreateDatabase()
engine.Dispose()

Dim conn As SqlCeConnection = New SqlCeConnection(connString)
conn.Open()

Dim cmd As SqlCeCommand = conn.CreateCommand()
cmd.CommandText = "CREATE TABLE BlobTable(name nvarchar(128), blob ntext);"
cmd.ExecuteNonQuery() 

cmd.CommandText = "INSERT INTO BlobTable(name, blob) VALUES (@name, @blob);"
Dim paramName As SqlCeParameter
Dim paramBlob As SqlCeParameter
paramName = cmd.Parameters.Add("name", SqlDbType.NVarChar, 128)
paramBlob = cmd.Parameters.Add("blob", SqlDbType.NText)
paramName.Value = "Name1"
paramBlob.Value = "Name1".PadLeft(4001)

cmd.ExecuteNonQuery()

The SQL Server Compact 4.0 release does not support syncing of data with SQL Server using technologies like Microsoft Sync Framework, or merge replication, or remote data access (RDA).

The generation of the Entity Data Model for SQL Server Compact will fail if there are duplicate constraint names in the SQL Server Compact schema.

In SQL Server Compact, the constraint names are unique within a table and this can allow duplicate constraint names in the database. The behavior is different from SQL Server, where the constraint names are unique across the database. If a SQL Server Compact schema has duplicate referential integrity (primary key – foreign key relationship) constraint names, the generation of the Entity Data Model using the ADO.NET Entity Framework’s Entity Data Model Wizard will fail. The workaround is to change the name of the duplicate constraint name to be unique across the database, like by adding the name of the table to the constraint name.

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For more information, see the SQL Server Compact Forum and the SQL Server Compact Team Blog.

• Make suggestions and file bug reports about the features or the user interface of SQL Server Compact at the MSDN product feedback Web site.

• Send suggestions or report inaccuracies in the documentation by using the feedback functionality in SQL Server Compact Books Online.

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