Add generic real-world extension method samples

docs/ado-net-extensions.md

@@ -161,3 +161,162 @@ When to use it:
 Tradeoff:
 
 - Higher memory use proportional to result size.
+
+## End-to-End Samples (Genericized)
+
+These samples mirror real production patterns while using generic names.
+
+## Sample 1: Stored Procedure with Multiple Result Sets + Null-Safe Reader Accessors
+
+```csharp
+var records = new Dictionary<string, GenericMessage>();
+
+using var con = Database.Open();
+using var cmd = con.CreateCommand()
+    .SetCommand(CommandType.StoredProcedure, "usp_get_messages");
+
+using var r = cmd.ExecuteReader();
+
+while (r.Read())
+{
+    var msg = new GenericMessage
+    {
+        Id = r.GetStringIfNotNull("id"),
+        Type = r.GetStringIfNotNull("type"),
+        Value = r.GetStringIfNotNull("value"),
+        State = (GenericMessageState)(r.GetInt32IfNotNull("state") ?? 0),
+        Date = r.GetDateTimeIfNotNull("date") ?? new DateTime(2099, 12, 31),
+    };
+
+    records.Add(msg.Id, msg);
+}
+
+if (r.NextResult())
+{
+    while (r.Read())
+    {
+        var messageId = r.GetStringIfNotNull("message_id");
+        if (!records.ContainsKey(messageId))
+            continue;
+
+        records[messageId].Items.Add(new GenericMessageItem
+        {
+            Id = r.GetStringIfNotNull("id"),
+            Type = r.GetStringIfNotNull("type"),
+            Value = r.GetStringIfNotNull("value"),
+        });
+    }
+}
+```
+
+Extension methods used:
+
+- `SetCommand(CommandType, string)`
+- `GetStringIfNotNull`
+- `GetInt32IfNotNull`
+- `GetDateTimeIfNotNull`
+
+## Sample 2: Stored Procedure with Input/Output Parameters + Result Check
+
+```csharp
+using var con = Database.Open();
+using var cmd = con.CreateCommand()
+    .SetCommand(CommandType.StoredProcedure, "usp_set_message_status")
+    .AddParameter(Database.GetParameterName("id"), DbType.String, (object)messageId)
+    .AddParameter(Database.GetParameterName("status"), DbType.Int32, (object)(int)status)
+    .AddParameter(Database.GetParameterName("note"), DbType.String, (object)note)
+    .AddParameter(Database.GetParameterName("result"), ParameterDirection.Output, DbType.Int32, 0, null)
+    .AddParameter(Database.GetParameterName("result_description"), ParameterDirection.Output, DbType.String, 1024, null);
+
+cmd.ExecuteNonQuery();
+
+var result = cmd.Parameters[Database.GetParameterName("result")] as IDataParameter;
+var resultDescription = cmd.Parameters[Database.GetParameterName("result_description")] as IDataParameter;
+
+if (result != null && result.Value != DBNull.Value && result.Value != null)
+{
+    if ((int)result.Value != 0)
+    {
+        var description = (resultDescription != null &&
+                           resultDescription.Value != DBNull.Value &&
+                           resultDescription.Value != null)
+            ? resultDescription.Value.ToString()
+            : "UNSPECIFIED";
+
+        throw new Exception($"{result.Value} - {description}");
+    }
+}
+```
+
+Extension methods used:
+
+- `SetCommand(CommandType, string)`
+- `AddParameter(...)` overloads with `DbType` and `ParameterDirection`
+- `DumpToString()` (optional diagnostic logging)
+
+## Sample 3: Parameterized `UPDATE` with Runtime SQL and ADO.NET Extensions
+
+```csharp
+using var conn = Database.Open();
+
+using var cmdUpdate = conn.CreateCommand()
+    .SetCommand($@"UPDATE {Database.DecorateName("transport_task")}
+SET {Database.DecorateName("confirmed")} = {Database.GetParameterName("confirmed")}
+WHERE {Database.DecorateName("id")} = {Database.GetParameterName("id")}")
+    .AddParameter(Database.GetParameterName("confirmed"), DbType.Int32, (object)1)
+    .AddParameter(Database.GetParameterName("id"), DbType.Guid, (object)taskId);
+
+if (cmdUpdate.ExecuteNonQuery() > 0)
+{
+    // updated
+}
+```
+
+Extension methods used:
+
+- `SetCommand(string, params object[])`
+- `AddParameter(string, DbType, object)`
+
+## Sample 4: Parameterized `SELECT` + Reader Mapping Method
+
+```csharp
+using var conn = Database.Open();
+
+using var cmd = conn.CreateCommand()
+    .SetCommand($@"SELECT * FROM {Database.DecorateName("transport_task")}
+WHERE {Database.DecorateName("id")} = {Database.GetParameterName("id")}")
+    .AddParameter(Database.GetParameterName("id"), DbType.Guid, (object)id);
+
+using var r = cmd.ExecuteReader();
+if (r.Read())
+    return ReadTask(r);
+
+return null;
+
+protected virtual MoveTask ReadTask(IDataReader r)
+{
+    var source = r.GetStringIfNotNull("Source");
+    var destination = r.GetStringIfNotNull("Destination");
+
+    return new MoveTask
+    {
+        Id = r.GetGuid(r.GetOrdinal("Id")),
+        Created = r.GetDateTime(r.GetOrdinal("Created")),
+        StartDate = r.GetDateTimeIfNotNull("StartDate"),
+        EndDate = r.GetDateTimeIfNotNull("EndDate"),
+        ExternalId = r.GetStringIfNotNull("ExternalId"),
+        TaskType = (TransportTaskType)(r.GetInt32IfNotNull("Type") ?? 0),
+        Source = string.IsNullOrEmpty(source) ? null : Deserialize<Address>(source),
+        Destination = string.IsNullOrEmpty(destination) ? null : Deserialize<Address>(destination),
+        Priority = r.GetInt32IfNotNull("Priority") ?? 0,
+    };
+}
+```
+
+Extension methods used:
+
+- `SetCommand(...)`
+- `AddParameter(...)`
+- `GetStringIfNotNull`
+- `GetDateTimeIfNotNull`
+- `GetInt32IfNotNull`