eXpress Persistent Objects for .NET

What's new in eXpress Persistent Objects for .NET v2011 vol 1?

• Extended Support for WCF Services – DevExpress have implemented IDataStore, ICachedDataStore, and ISerializableObjectLayer providers allowing you to easily tunnel your data via WCF services. Generally, all you have to do is derive your service from a corresponding XPO service class (DataStoreService, CachedDataStoreService, or SerializableObjectLayerService), modify service binding settings and pass the service's URL to your client application. Creating distributed applications with XPO is now a breeze.
• Default Sorting Options for Data Sources - DevExpress have added a DefaultSorting property allowing you to specify how XpoDataSource, XPInstantFeedbackSource, and XPServerCollectionSource contents are sorted by default, when sort order is not specified by the bound control.
• Support for In-line Parameters - Int32, Boolean, string, and enum constant values passed as criteria operands are automatically embedded as in-line parameters to resulting SQL queries. This improves performance when you query for data using multiple criteria with matching constant parameters.
• Support for OUTER APPLY Operators - DevExpress have implemented support for OUTER APPLY operators found in MS SQL Server (version 2005 and later) and MS SQL Server Compact (version 3.5 and later). You can now calculate nested aggregates and group by aggregates – the SQL query generator will automatically exploit OUTER APPLY operators for subqueries.
• LINQ to XPO Enhancements - You can now use custom functions in LINQ to XPO expressions.
• VistaDB Provider Assembly Dynamic Loading - DevExpress have continued their ADO.NET provider assembly dynamic loading initiative started in v2010 vol 2 and removed references to the VistaDB provider assembly. XPO now has references only to .NET Framework assemblies - System.Data.SqlClient (for MS SQL Server support) and System.Data.OleDb (for MS Access support).
• Improved Persistent Classes Wizard - The wizard stores the most recently used connection settings in a file located within a user's local AppData folder. The corresponding wizard page will be automatically populated with stored connection settings each time you invoke the wizard.
• Enhanced Smart Tag Menu for XPDataView and XPView - Smart Tag menus for XPDataView and XPView controls have been extended with a Populate Properties item allowing you to automatically populate the control with columns based on a persistent class selected via ObjectClassInfo.

What's new in eXpress Persistent Objects for .NET v2010 vol 2?

• Support for Stored Procedures - With DXperience v2010 vol 2, DevExpress have introduced support for stored procedures within the eXpressPersistent Objects Library. You can now directly call existing stored procedures and handle the returned result sets. In addition, you can map persistent classes to MS SQL Server and Oracle database views with the help of INSTEAD-OF triggers and stored procedures. To simplify implementation, the Generating Persistent Classes wizard has been extended with a corresponding page and options, generating all the auxiliary and helper classes, as well as DDL (Data Description Language) code for you.
• Support for Direct SQL Queries - In addition to stored procedures, you can now execute direct SQL queries against a database and obtain query results as scalar values, result sets or object collections.
• Universal Data Source for Result Sets - With the new data source control - XPDataView - any result set you obtain from a database can be easily visualized in data-aware controls. The data source provides built-in filtering and sorting capabilities to shape resulting data as needed.
• Instant Feedback UI Data Source - XPO provides a new data source control - XPInstantFeedbackSource - allowing you to activate the DevExpress Instant Feedback UI in your DevExpress WinForms Grid and SearchLookUpEdit Controls.
• Explicit Transactions - You can now manually maintain explicit transactions within sessions or units of work, or allow XPO to do this automatically, via specially designed units of work (ExplicitUnitOfWork). Explicit transactions simplify managing object changes within a session or unit of work and also come in handy in scenarios when normal transactions cannot be used for batch object updates. While in an explicit transaction mode, changes made to persistent objects are temporarily stored in a database, allowing you to access these objects as if they were already stored in the database. All temporary changes can be finalized or rolled back at any time - just like normal transactions.
• ADO.NET Provider Assembly Dynamic Loading - With v2010 vol 2, XPO uses loose coupling to load ADO.NET provider assemblies dynamically. In essence, XPO has no direct reference to most of the ADO.NET providers, except for references to System.Data.SqlClient (for MS SQL Server support), System.Data.OleDb (for MS Access support) and VistaDB. You can now use any specific version of the provider without having to recompile the DevExpress.Xpo.vXXX.Providers assembly.

Easy to Use and Highly Productive

With eXpress Persistent Objects for .NET, you never again have to deal with table mapping - all you need is to define persistent object classes, and XPO.NET will generate your database for them automatically. It will transparently handle relationships between classes and object inheritance. But you never sacrifice ease-of-use for flexibility. If you ever need more control over O/R mapping, you can simply use the built-in attributes to provide additional mapping information to XPO.NET and thus address any business requirement

With XPO.NET, you can start your database application development directly from the object model. You never have to spend your time on tables, columns, keys and constraints - just roll up your sleeves and focus on writing code! XPO.NET will keep your database structure up-to-date. It will allow you to focus on important application-specific issues, rather than on pain-in-the-neck generic purpose database issues.

Like all Developer Express .NET technologies, XPO is available with full source code.

Features:

• Transparent and controllable Object-Relational Mapping (ORM) system - By using .NET Reflection and attributes system, XPO is able to map properties of business objects to relational database tables. Object associations (one-to-one, one-to-many, many-to-many), aggregation and inheritance are all FULLY supported
• Bindable Object Collections - With XPO, you can retrieve collections of persistent objects and bind them to UI controls with ease
• Object Queries - You can specify filtering and retrieval criteria using straightforward object syntax
• Database Generation and Updates - XPO allows you to generate or update database tables based upon the definitions of your persistent object classes
• Support for MS Access, MS SQL Server, MySQL, Oracle, PostgreSql, Firebird, PervasiveSQL, VistaDB, SQL Anywhere, Advantage, DB2 and Sybase
• Delayed Loading for Object Properties - With XPO.NET, you can improve application performance by delaying the loading of certain properties which are rarely used or contain large amounts of data
• Add Persistence to Existing Inheritance Hierarchies via Interfaces
• XML Model with Custom Attributes - XPO now uses an abstract metadata model instead of .NET Reflection. .NET Reflection metadata can be obtained by means of ReflectionDictionary which is used by default. The XmlDictionary class extends ReflectionDictionary with the ability to supply XML data specifying mapping information and custom attributes for modifying the data accumulated via .NET Reflection
• Transaction Support - XPO provides transactions in the same manner as ADO.NET. You can easily Begin the transaction, then Commit or Rollback with the appropriate Session methods
• Custom OID - Key attribute has been added. A class property - of any supported data type - annotated with this attribute is treated as a key. Key auto-generation is supported only for the Guid and Int32 data types
• Optimistic Locking - Optimistic concurrency is supported for updates ("First in wins" rule)
• Explicit declaration of a string field of unlimited size - Unlimited Text/Memo field size can be defined by specifying the Size attribute with the Unlimited constant
• Remoting Support - All base XPO classes are derived from MarshalByRefObject to provide remote object access using the .NET Remoting infrastructure
• Support for Existing Database Schema
• Persistent Class Template - Provides the easiest and fastest way to add persistent classes to your project
• XtraGrid Integration - The new xpoXtraDataAdapter component allows you to use the advanced features provided by the XtraGrid for displaying, sorting and grouping data retrieved by XPCollection
• Advanced Criteria System - Criteria operators allow you to build complex criteria representing the logical expressions used to filter XPCollection contents
• Session, Collection Components - These components allow you to set the DataSource and bind them to any visual component such as grid, edit and other control at design time
• IBindingList Collection Behavior - XPCollection supports IBindingList and you can add or remove collection items via this interface at run time
• Custom Constraints and Indexes - Advanced metadata attributes allow you to specify database constraints and indexes for a persistent property or a field. By handling the OnSchemeInit event of the Session object you can enforce any custom database modifications
• Database Integrity Validation - XPO.NET keeps the underlayed database up-to-date and integrated automatically, unless you choose to disable this functionality
• Advanced Event System - In order to perform custom actions during object and session manipulations, you can employ the events raised when session / transaction state is changed or the underlying database metadata is about to be modified