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Welcome to. Introduction to Data Access with Spring.NET Mark Pollack Principal CodeStreet LLC.

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Presentation on theme: "Welcome to. Introduction to Data Access with Spring.NET Mark Pollack Principal CodeStreet LLC."— Presentation transcript:

1 Welcome to

2 Introduction to Data Access with Spring.NET Mark Pollack Principal CodeStreet LLC

3 Overall Presentation Goal Learn about Spring.NET's support for ADO.NET, O/R Mappers, and transaction management abstraction

4 Speaker’s Qualifications Mark Pollack is a founding partner at CodeStreet LLC, a software and consulting firm in the financial services industry..NET and J2EE architect and developer specializing in front office solutions, EAI, and message based middleware Spring Developer (2003) JmsTemplate Founder of Spring.NET (2004) Co-lead of Spring.NET with Aleks Seovic

5 Outline Quick overview of Spring.NET.NET Data Access Landscape ADO.NET Framework NHibernate integration Transaction management

6 Spring.NET Overview Concepts in Spring are not platform specific Want to build.NET apps in a similar way Need for an application framework Not a blind port of Spring Version 1.0 released September 2005

7 Spring.NET subsystems Core AOP Services (Exporters) Data Access WebDesktop 3 rd Party Integration

8 Data Access Landscape Wide range of data access strategies and technologies Developer toolbox has matured PEAA – Fowler Know how to ‘codify’ best practice patterns Technologies ADO.NET, O/R Mappers Transaction Management Local –ADO.NET –System.Transactions (.NET 2.0) Distributed - MS-DTC/COM+Services –EnterpriseServices (.NET 1.1) –System.Transactions (.NET 2.0) –.NET 3.0 (WinFX)

9 Spring Data Access Provide uniform best practice approach across data access technologies. IoC integration Transaction management Programmatic and declarative Resource management ‘Template’/callback APIs Exception Translation Added value Make ‘native’ APIs easier to use – ADO.NET Higher level encapsulation of Data Access –DAO support classes, “AdoOperation” objects

10 Spring.NET Data Access “Spring.Java” users should feel right at home ADO.NET, to first order Java ported O/R Mappers, to second order. ADO.NET framework NHibernate support iBatis.NET under development. Early Adopter stage Well hedged by “Spring.Java” design A small feature set used in production now. –Daily P/L calculations and reporting for a major hedge fund.

11 ADO.NET API overview Uniform API between “Text SQL” and Stored procedures IDbCommand property: CommandType IDbParameters used extensively In, Out, InOut, Return Few easy methods on Command class ExecuteScalar, ExecuteNonQuery, ExecuteReader DataSets – DataAdapter + CRUD IDbCommands Parameter binding By name is prevalent in API Generally, no fallback to generic placeholder if provider supports named parameters Transaction object Can assign to a command object.

12 Motivations for ADO.NET framework Provide usable provider independent API No factory in BCL (.NET 1.1) Simplistic and at times incomplete interfaces IoC integration Connection String management Easier parameter management BCL interfaces leads to verbose code Exception Handling Not singly rooted (.NET 1.1) Base exception + error code (.NET 2.0) No portable “DAO” exception hierarchy

13 Motivations for ADO.NET framework II Centralize resource management Connection, Command, DataReader ‘using’ is A Good Thing. –Does reduce try/finally verbosity but ‘no catch’ Transaction management Ad-hoc passing around of Transaction object API Quirks Exception reading a null from IDataReader

14 AdoTemplate Execute() ICommandCallback, CommandDelegate Use of delegates – i.e. stateless callbacks. Use of variable length arguments, boxing ExecuteScalar(), ExecuteNonQuery(), Query() IRowCallback, IRowMapper, IResultSetExtractor Variations with IDbCommandSetter, IDbCommandCreator One “inline” parameter –string name, Enum dbType, int size, object parameterValue Factory Method for creating IDbParameters

15 Callback Interface Central method of AdoTemplate Resource Management Transaction Aware public interface IAdoOperations {... public Object Execute(ICommandCallback action); public Object Execute(CommandDelegate del); } public interface ICommandCallback { Object DoInCommand(IDbCommand command); } public delegate Object CommandDelegate(IDbCommand command);

16 Standard ADO.NET public class NativeAdoTestObjectDao : ITestObjectDao { // Connection String Property... public void Create(string name, int age) { using (SqlConnection connection = new SqlConnection(connectionString)) { string sql = String.Format("insert into TestObjects(Age, Name) " + "VALUES ({0}, '{1}')", age, name); using (SqlCommand cmd = new SqlCommand(sql, connection) { connection.Open(); comm.ExecuteNonQuery(); }

17 AdoTemplate Example public class TestObjectDao : AdoDaoSupport, ITestObjectDao { public void Create(string name, int age) { AdoTemplate.ExecuteNonQuery( String.Format(CommandType.Text, "insert into TestObjects(Age, Name) " + "VALUES ({0}, '{1}')", age, name)); }

18 Connection String Management Custom Schema to set common connection string properties XML’ized.NET 2.0 Connection String builders

19 Parameter Creation Use any provider Sql Type Enumeration Helper methods for parameter creation AddOut, AddInOut, DataSet related IDbParameters parameters = adoTemplate.NewDbParameters(); parameters.Add("Name", DbType.String, 12).Value = name; parameters.Add("Age", SqlDbType.Int).Value = age; adoTemplate.ExecuteNonQuery(CommandType.Text, sql, parameters);

20 AdoOperations OO model for DB operations Preferred approach AdoQuery - Result set mapping to objects AdoNonQuery- Insert/Update/Delete AdoScalar – Return single value StoredProcedure out parameters and multiple result sets AdoDataSetQuery* – Return DataSet Use of ICommandCreater implementation for efficient parameter re-creation.

21 public class TestObjectQuery : MappingAdoQuery { private static string sql = "select TestObjectNo, Age, Name from TestObjects"; public TestObjectQuery(IDbProvider dbProvider) : base(dbProvider, sql) { CommandType = CommandType.Text; } protected override object MapRow(IDataReader reader, int num) { TestObject to = new TestObject(); to.ObjectNumber = reader.GetInt32(0); to.Age = reader.GetInt32(1); to.Name = reader.GetString(2); return to; } MappingAdoQuery NullMappingDataReader

22 IDataReaderWrapper NullMappingDataReader implementation Specified in AdoTemplate Say goodbye to code like this… to.ObjectNumber = (!reader.IsDBNull(0)) ? reader.GetInt32(0) : -1; to.Age = (!reader.IsDBNull(1)) ? reader.GetInt32(1) : -1; to.Name = (!reader.IsDBNull(2)) ? reader.GetString(2) : String.Empty; TestObjectQuery testObjectQuery = new TestObjectQuery(dbProvider); IList testObjectList = testObjectQuery.Query();

23 AdoNonQuery public class CreateTestObjectNonQuery : AdoNonQuery { private static string sql = "insert into TestObjects(Age,Name) values public CreateTestObjectNonQuery(IDbProvider dbProvider) : base(dbProvider, sql) { DeclaredParameters.Add("Age", DbType.Int32); DeclaredParameters.Add("Name", SqlDbType.NVarChar, 16); Compile(); } public void Create(string name, int age) { ExecuteNonQuery(name, age); } Variable length arguments

24 StoredProcedure ADO.NET supports discovery of Stored Procedure parameters. public class CallCreateTestObject : StoredProcedure { public CallCreateTestObject(IDbProvider dbProvider) : base(dbProvider, "CreateTestObject") { DeriveParameters(); Compile(); } public void Create(string name, int age) { ExecuteNonQuery(name, age); }

25 StoredProcedure Easy access to out parameters public class CallCreateTestObject : StoredProcedure { public CallCreateTestObject(IDbProvider dbProvider) : base(dbProvider, "CreateTestObject") { DeriveParameters(); Compile(); } public void Create(string name, int age) { IDictionary inParams = new Hashtable(); inParams["name"] = name; inParams["age"] = age; IDictionary outParams = ExecuteNonQuery(inParams); }

26 O/R Mapping Support Easy ‘porting’ code/concepts from.NET versions of Java O/R NHibernate IBatis.NET Two levels of support IoC helpers for central object injection/configuration Template classes for resource/tx management. Others as well…. DB40 WilsonORM Gentle.NET Neo Microsoft - ADO.NET 3.0 LINQ for X.

27 NHibernate Example public class NativeNHTestObjectDao : ITestObjectDao { // SessionFactory property... public void Create(TestObject to) { ISession session = null; ITransaction transaction = null; try { session = SessionFactory.OpenSession(); transaction = session.BeginTransaction(); session.Save(to); transaction.Commit(); } catch { if(transaction != null) transaction.Rollback(); throw; } finally { if(session != null) session.Close(); }

28 NHibernateTemplate DAO Implementation public class NHTestObjectDao : HibernateDaoSupport, ITestObjectDao { [Transaction()] public void Create(TestObject to) { HibernateTemplate.Save(to); } Support for declarative and programmatic transaction management for any data access technology

29 Microsoft Transaction Management LocalDistributedDeclarativeProgrammatic ADO.NET (1.1)  EnterpiseServices (1.1)  System.Transactions (2.0) .NET 3.0 (WinFX) The sweet spot Declarative transaction management + local transactions

30 ADO.NET Transactions ADO.NET Connection/Transaction pair. Associate multiple DbCommands with the same transaction API –Transaction.Begin(), Commit(), Rollback()

31 EnterpriseService Transactions Access to COM+ services MS-DTC for transaction management Declarative transaction demarcation features Cumbersome to deploy and develop Declarative demarcation only at class level NB: Spring.Services provides an EnterpriseServicesExporter Originally required inheriting from ServicedComponent Providers are aware of transaction context of the thread Similar to approach in Spring Template/TxMgr but part of standard ADO.NET API. Always uses MS-DTC to access database API ServiceDomain.Enter(), Leave; ContextUtil.SetAbort()

32 .NET 2.0 Transactions Easy to use programming model Providers are aware of transaction context of the thread Uses most efficient means of db access Local transactions can be promoted to distributed –“Promotable Single Phase Enlistment” (PSPE) Only Microsoft providers for now –SqlServer 2005, MSMQ. API new TransactionScope();.Complete(), Dispose(), Transaction.Current.Rollback()

33 Transaction Managers AdoPlatformTransactionManager Local transactions ServiceDomainPlatformTransactionManager Distributed transactions TxScopePlatformTransactionManager Local or Distributed as needed. Switching is just a small configuration change. Callback interfaces ITransactionCallback

34 TODOs Use ADO.NET and O/R Mappers within in same transaction “KeyHolder” to easily access created keys Custom schema for transaction mgmt DataSet functionality LOB support Nested Transactions…

35 Summary Spring’s approach to Data Access is very applicable to.NET development ADO.NET framework will give you real productivity gains Give it a whirl Feedback more than welcome!

36 Q&A



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