Say we have Four different Databases and their connections
as well which are stored in configuration file like web.Config or
<App-Name>.config and we are in need to
connect to different database depending upon user type
Connection Strings We Have:
<add name = "OracleConString"
connectionString =
@"provider=MSDAORA;data source=ORCL;user id=SCOTT;password=TIGER"
/>
<add name = "OdbcConString"
connectionString =
@"Driver={Microsoft Access Driver (*.mdb)};DBQ=c:\Northwind.mdb"
/>
<add name "OleDbConString"
connectionstring =
@"Provider=SQLOLEDB.1;Password=pw;Persist Security Info=False" />
User ID=admin;Initial Catalog=biblio;Data Source=betav9;
Use Procedure for Prepare=1;Auto Translate=True;Packet
Size=4096;
Workstation ID=BETAV9;Use Encryption for Data=False;
Tag with column collation when possible=False"/>
<add name ="SqlServerConString"
connectionString = @"data source = .\SQLEXPRESS; Integrated Security =
SSPI; AttachedDBFileName = abc.mdf; User Instance = true"
providerName="System.Data.SqlClient"/>
When we have taken a decision over user type, we may pass a
value to if else structure or case. Depending
upon the value you can get the type of connection to
a database we want.
Object dbCon = null;
switch(userType)
{
case "sqlConnection"
dbCon = new SqlConnection("SqlServerConString");
// provide appropriate sql command
break;
case "OleDbConnection"
dbCon = new
System.Data.OleDb.OleDbConnection("OleDbConString");
// provide appropriate sql command
break;
case "OdbcConnection"
dbCon = new OdbcConnection("OdbcCongString");
// provide appropriate sql command
break;
case "OracleConnection"
dbCon = new OleDbConnection ("OracleConString");
// provide appropriate sql command
break;
}