ADO.NET SQL Server connection

SQLConnection.cs

private string connectionString = @"Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=WPF_Data;Integrated Security=True;Connect Timeout=60;Encrypt=False;TrustServerCertificate=False;ApplicationIntent=ReadWrite;MultiSubnetFailover=False";
string SQL_SELECT = "SELECT * Data_Table";

SqlConnection conn = new SqlConnection(connectionString);
SqlDataAdapter da = new SqlDataAdapter();
SqlCommand sql = conn.CreateCommand();
sql.CommandText = SQL_SELECT;
da.SelectCommand = sql;

DataSet ds = new DataSet();
da.Fill(ds);