1. Опит в използването на ODP.NET с Oracle 9i
Лектор: Иван Симеонов
ТехноЛогика ЕООД

2. Какво е Oracle Data Provider for .NET (ODP.NET)
ASP.NET
VB.NET C#
C++.NET
OLE DB .NET
ODBC .NET
ODP .NET
ORACLE OLE DB
ORACLE ODBC
The introduction of the Microsoft .NET Framework has produced a new Windows application server environment different from COM. With COM, data can be accessed from an Oracle database through either Oracle Objects for OLE (OO4O), ADO/OLE DB, or ODBC. In a .NET environment, users still can access the Oracle database via OLE DB and ODBC using a data access bridge provided by Microsoft. For OLE DB, this bridge is OLE DB .NET; For ODBC, the bridge is ODBC .NET. These bridges provide interoperability between the managed .NET layer and unmanaged COM or Win32 layer. The Oracle Data Provider for .NET (ODP.NET) represents the third method for accessing the Oracle database.
DIFFERENCES WITH OTHER .NET DATA PROVIDERS
Among the three data access methods, ODP.NET is the most native to the .NET environment, bypassing the need for OLE DB or ODBC. It features high performance access to the Oracle database, while providing access to advanced Oracle functionality not available through OLE DB .NET and ODBC .NET. Similar to OLE DB .NET and ODBC .NET, ODP.NET can be used from any .NET language, such as C# and Visual Basic .NET. An important distinction is that ODP.NET does not use an extra data access bridge; thus, it will have better performance than OLE DB .NET and ODBC .NET. Additionally, because these .NET bridges are built for generic data sources, they do not provide full access to advanced database functionality. These three .NET data providers are shown in Figure.  
ORACLE DB

3. ODP.NET Обектен модел Disconnected Layer Connected Layer (ODP.NET)
Data
Layer
Oracle
DataAdapter
OracleCommand
Builder
DataSet
Oracle
DataReader
Oracle
Command
Business Object
Oracle
Transaction
Oracle
Connection
Oracle

4. Основни характеристики на ODP.NET
Full PL/SQL support
Packaged, non-packaged, anonymous, autonomous
Batch SQL available with anonymous PL/SQL
Native Oracle data types
LOBs, REF Cursor, Date, TimeStamps, Long, Raw, etc.
Connection pooling
Min, Max, Timeout, Lifetime, Increment, Decrement
Transactions
Enterprise Services via Oracle Services for MTS
Savepoints
Globalization
Full Unicode support
Client settings are used to display Oracle data in locale-specific manner
Transparent application failover
Notification callbacks
Here are some of the ODP.NET features that were not previously available to ADO, OLE DB .NET, nor ODBC .NET users:
More robust anonymous (use PL/SQL blocks in .NET code) PL/SQL support
Native Oracle types and safe type mapping
Connection Pooling Configuration
PL/SQL can be used more flexibly with ODP.NET. Anonymous PL/SQL allows the client to batch SQL calls to the DB. When you embed multiple commands within anonymous PL/SQL, only one roundtrip to the database is made, thereby improving data access performance.
Native Oracle types allow users to use Oracle data types within their .NET programs. This makes using Oracle data easier and much more flexible from .NET. It saves developers and applications from doing unnecessary conversions to .NET data types if they are not needed. Each native Oracle data type can be mapped to a respective .NET data type.
Because Oracle data types tend to be higher precision than .NET types, Oracle allows conversion between the two types without losing data. This is known as safe type mapping. For example, Oracle Number can hold 38 digits, whereas .NET Decimal only holds 28. Safe type mapping allows converting Oracle Number to .NET byte array or .NET string and back to Oracle Number without losing any data.
Creating DB connections is resource intensive. As such, connection pooling is an invaluable performance tuning option. Previously, .NET developers could only set timeout values for their connection pools. With ODP.NET, connection pools are very flexible to configure for any type of application user load.

5. Основни характеристики на ODP.NET - продължение
Parameters
PL/SQL Associative Array data type
Parameter Array binding
Named and positional parameters
XML DB
XML repository
Native XMLType
XML stored as CLOB or object
Schema and non-schema-based
XML Views
PL/SQL Associative Array
Parameter Array Binding
Named parameter binding and array binding
The associative array, also known as index-by table, is a PL/SQL data type similar to a hash table. It can be bound as an ODP.NET parameter and passed as an array to .NET.
Parameters can be bound to PL/SQL or SQL calls either through using named parameters or by sequential position. Array binding improves application performance by reducing the number of roundtrips for DML primarily. For example, without array binding, updating 100 rows would require 100 DB server roundtrips. With array binding, only one roundtrip is necessary to do all 100 updates. This makes applications perform considerably faster.
ODP.NET has the flexibility to bind parameters by position or name, whichever best fits the developer’s preference.
DataAdapter Requery allows developers to reuse the same query result for multiple data fills of DataSet. This feature saves applications from having to re-query the DB for the same set of data.
XML DB is a high performance XML storage and retrieval technology in the Oracle DB. XML DB stores XML natively in the DB with its own data type, XMLType. ODP.NET exposes XMLType as a native type within .NET to manipulate XML and share XML with Microsoft’s XML services, such as XMLReader. ODP.NET can access relational and object-relational data as XML with the ability to query and save XML from the database easily.

6. Oсновни предимства на ODP.NET
Multiple Active Result Sets (MARS)
Native XML Data Type
Result Set Retrieval Tuning Options
Configurable LOB Retrieval
Array Parameters

7. Oracle Helper ExecuteDataSet – 6 overloads
ExecuteFunction – 9 overloads
ExecuteReader – 6 overloads
ExecuteScalar – 6 overloads
ExecuteNonQuery – 6 overloads
ExecuteXMLReader – 6 overloads

8. Проблеми с ODP.NET Липсва DeriveParameters за PL/SQL процедури
PLSQL Associative Arrays без стойност на елемент
Не поддържа varray като параметър
ExecuteScalar не работи с PL/SQL Functions без RefCursor
Разлика в типовете данни

9. Добри практики при използването на ODP.NET
Използвайте connection pooling
Отстранявайте ODP.NET обектите, когато приключите работа
Минимизирайте roundtrips
Оптимизиране на single statement (SELECT)
Използвайте FetchSize (OracleDataReader) и RowSize (OracleCommand)
Използвайте DataAdapter.Requery
Намалява roundtrips при повторно изпълнение на команда

10. Добри практики при използването на ODP.NET - продължение
Оптимизиране на multi-statement
Изпълнявате много и различни команди?
Използвайте anonymous PL/SQL
Използвайте групови команди
Изпълнявате една команда много пъти?
Използвайте parameter array binding
Използвайте PL/SQL associative arrays

11. Добри практики при използването на ODP.NET - продължение
Използвайте OracleRefCursor class
Данните се извличат, когато е необходимо
Използвайте Oracle LOB classes (DML)
Няма необходимост да изтегляте данните за да променяте или добавяте LOBs
Желаете данните в LOB на един път?
Използвайте InitialLOBFetchSize, за да оптимизирате извличането на LOB
Желаете да извлечете LOB по-късно?
По подразбиране, ODP.NET използва LOB locators

12. Добри практики при използването на ODP.NET - продължение
Използвайте PL/SQL пакети
Управлявайте транзакциите от .NET
Когато е възможно, използвайте multiple RefCursors
Използвайте собствен error handling (Exceptions.ApplicationBlock) …

13. Други .NET Providers за Oracle
Microsoft .NET Data Provider for Oracle
Corelab OraDirect .NET Data Provider
DataDirect Connect for .NET

14. Кой .NET Provider да използваме
За малки приложения и бърза разработка – MS Data Provider for Oracle
За пълно използване на възможностите на Oracle DB и висока производителност – ODP.NET