19. Connection strings, authentication and connecting from every technology

Server=tcp:myserver.database.windows.net,1433;   ← host (or ".\SQLEXPRESS", "localhost", "(localdb)\MSSQLLocalDB"), port 1433
Database=Shop;                                    ← (= Initial Catalog)
User ID=shop_app;Password=***;                    ← SQL authentication   OR   Trusted_Connection=True / Integrated Security=SSPI (Windows auth)
Encrypt=True;TrustServerCertificate=False;        ← TLS (Encrypt=True is the default since Microsoft.Data.SqlClient 4.0)
Connection Timeout=30;                            ← seconds to wait for a connection
MultipleActiveResultSets=False;                   ← MARS
Application Name=Shop.Api;                        ← shows in sys.dm_exec_sessions — great for diagnostics
Max Pool Size=100;Min Pool Size=0                 ← connection pooling (on by default)

// ADO.NET done right: async, parameterised, pooled, disposed
await using var conn = new SqlConnection(cs);
await conn.OpenAsync(ct);
await using var cmd = new SqlCommand("SELECT Id, Name FROM dbo.Products WHERE CategoryId = @cat", conn);
cmd.Parameters.Add("@cat", SqlDbType.Int).Value = categoryId;
await using var reader = await cmd.ExecuteReaderAsync(ct);
while (await reader.ReadAsync(ct)) Console.WriteLine($"{reader.GetInt32(0)} {reader.GetString(1)}");