#23 @ASP.NE C# में SQL Server LocalDB connect करने का सही तरीका using AttachDbFilename.

✔ |DataDirectory| automatically maps to App_Data
✔ No absolute path issues

❌ NOT recommended (Absolute path)
AttachDbFilename=C:\Users\Naveen\source\repos\Project\App_Data\MyDatabase.mdf
This fails after publish.

4️⃣ C# Code to Connect
using System.Data.SqlClient;

string cs = ConfigurationManager.ConnectionStrings["MyConn"].ConnectionString;

using (SqlConnection con = new SqlConnection(cs))
{
con.Open();
// connection successful
}

5️⃣ Common Errors & Fixes
❌ Error: Cannot open database requested by the login

✔ Fix:

Stop IIS Express

Close Visual Studio

Reopen project

Run again

❌ Error: Database already exists

✔ Fix:
Remove duplicate LocalDB files from:

C:\Users\Naveen\

❌ Error: Login failed for IIS APPPOOL

✔ Fix:
LocalDB uses Windows Authentication
No SQL login required
Ensure:

Integrated Security=True

6️⃣ IIS / IIS Express Notes

LocalDB:

Works with IIS Express

NOT recommended for production IIS

For production → use SQL Server Express / Standard

7️⃣ Best Practice

✔ Development → LocalDB + AttachDbFilename
✔ Production → SQL Server + normal connection string

Видео #23 @ASP.NE C# में SQL Server LocalDB connect करने का सही तरीका using AttachDbFilename. канала IT TECH