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Application Migration

Application Migration Agenda

• Typical Client Applications• JDeveloper Application Migration Assistant • Typical Middleware and Access Methods used to

connect to RDBMS• Web Applications• MS Access Applications• Delphi Applications• ESQL/C Applications

Application Migration Typical Client Applications

• Typical client software• Visual Basic• VC++ • C#• ESQL/C• 4GL• Access• Delphi• Web Applications

• Typical middleware• ODBC• ODBC + Access methods (DAO, RDO, ADO)• OLE/DB• .NET• BDE

Application Migration JDeveloper Application Migration Assistant

• Identifies and allows easy navigation between statements in the code that may require modification to work on the Oracle platform.

• Analyzes complete projects or single files.• Generates an Analysis Report that summarizes

project statistics.• Uses regular expressions in XML format that provide

a search rule capability to identify issues • Allows rules to be customized so you can augment

the search capability

Application Migration ODBC drivers for Oracle

• Oracle ODBC www.oracle.com• Microsoft ODBC www.eu.microsoft.com• Datadirect ODBC www.datadirect.com

Application Migration Microsoft ODBC

• Less supported functionality than Oracle’s

• No Built-in Scrollable Cursor Support

• ResultSets supported via PL/SQL Indexed by Arrays only (non transparent support)

Application Migration Oracle ODBC

• Based on latest Oracle OCI• Emulation capabilities

• Built-in Scroll Cursor• ResultSets are supported transparently

• Supports an Array Interface

• Supports LOB

Application Migration Datadirect ODBC

• Built-in Scroll Cursor• ResultSets supported transparently• Full LOB Support• Supports an Array Interface

• Additional cost

Application Migration Microsoft Access Methods - ODBC

• MS Access uses DAO only• VB / SQL Server applications historically use

RDO• RDO cursor libraries provide support for

scrolling cursors even if the ODBC driver does not (e.g. RDO client batch cursor library)

• make sure to select PK columns in the base SELECT statement

• ADO and .NET are the more recent access methods.

• Oracle provides an OLE/DB provider with the same level of functionality as its ODBC driver

• OO4O is an OLE server providing full native support for Oracle (written ib OCI)

• Available through VB Object and VC++ Class

• Proprietary Interface

• Do not confuse OO4O and OLE/DB

Application Migration Microsoft Access Methods – OLE/DB

Application Migration Microsoft Access Methods - .NET

• Oracle provides a .NET driver the ODP.Net• XML Support

• Resultset Support

• Minor changes required to SQLHelper class• .NET Developer Center

• http://www.oracle.com/technology/tech/dotnet/index.html

• Oracle Developer Tools for Visual Studio .NET

• MS applications tend to use Active Server Pages on the client.

• ASPs tend to use ADO to communicate to the Database backend although .NET ODP is now becoming common.

• Can be easily migrated to use the Oracle OLE/DB provider behind ADO

• ODBC also possible via OLE/DB provider for ODBC

• Could leave as is or migrate to JSP (Java Server Pages).

Application Migration Web Applications

Application Migration Delphi Applications

• Delphi 6 normally uses BDE

• Borland Database Engine (BDE) maps quite well to Oracle although performance is not good when run against >8i.

• Native access to Oracle should be used (e.g. CoreLab’s ODAC (http://www.crlab.com) (Oracle Data Access) – same as BDE but closer to Oracle (directly in OCI)S

Application Migration Delphi Applications

• Use the BDE with native Oracle Driver, ODAC (preferably) or ADO.

• Use local Schema Cache• Define Rowsetsize to use Arrayinterface• Object Names should be in capital Letters• Use Varchar2 Datatype in the Database• Not portable SQL needs to be changed

• Outer Joins• Select List Subqueries …

• Null Value Handling needs be checked

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