ADO.NET 3.5 Cookbook, 2nd Edition

1.1. Storing Connection Strings

Problem

You need to choose the best place to store connection strings that you need in your application to increase maintainability, simplify future modifications, and eliminate the need to recompile the application when it is modified.

Solution

Solutions include storing the connection string in an application configuration file or the Windows registry, hardcoding the connection string in your application, representing it using a Universal Data Link (UDL) file, and storing it in a custom file. Some of these techniques are better than others, and some are completely inadvisable. This solution explores and discusses the alternatives.

The .NET Framework 2.0 introduced protected configuration as a mechanism for encrypting stored connection strings used by ASP.NET applications. It also introduced the connectionStrings configuration element to specify a collection of database strings. In prior versions, connection strings were stored in the appSettings element.

Discussion

A connection string is made up of a semicolon delimited collection of attribute/value pairs that define how to connect a data source. Although connection strings tend to look similar, the available and required attributes are different depending on the data provider and on the underlying data source. There are a variety of options providing differing degrees of flexibility and security.

ora: Persist Security Info

The Persist Security Info connection string attribute specifies whether the data ...