If you use MSSQL in your application, then your user must have access to SQL Server to use it. However, it is not normal to ship SQL Express with your app setup - the user may already have SQL Server installed on an existing computer.
If this is a single user database system, consider not using SQL Server. If you use SqlCE instead, the code for the database is included in the .NET framework so no additional installation is required. SqlCE is a cut down version of MsSql which is single user only, and does not support some of MsSql more advanced features.
"Here im using SQL Express 2005(.mdf)database.
When i Installed both SQlCE and my .net application and my application is showing an error "An error has
occured while establising a connnection to the server.when connecting to sql server 2005....error-26
error locating server/Instance specified"
Please give ur advice"
I'm not sure what you have tried to do here: SQLCE won't open a .MDF database: convert it to an SQLCE database instead if you are going to go that route. There is a utility here to do that:
SQL Server to SQL Server Compact Edition Database Copy Utility[
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