Oracle9iAS TopLink Tutorials Release 2 (9.0.3) August 2002 Part No. B10062-01 Oracle9iAS TopLink Tutorials, Release 2 (9.0.3) Part No. B10062-01 Copyright © 2002, Oracle Corporation. All rights reserved. The Programs (which include both the software and documentation) contain proprietary information of Oracle Corporation; they are provided under a license agreement containing restrictions on use and disclosure and are also protected by copyright, patent and other intellectual and industrial property laws. Reverse engineering, disassembly or decompilation of the Programs, except to the extent required to obtain interoperability with other independently created software or as specified by law, is prohibited. The information contained in this document is subject to change without notice. If you find any problems in the documentation, please report them to us in writing. Oracle Corporation does not warrant that this document is error-free. 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Contents Send Us Your Comments .................................................................................................................. vii Preface............................................................................................................................................................ ix Intended Audience ................................................................................................................................ ix Documentation Accessibility ................................................................................................................ x Structure ................................................................................................................................................... x Related Documents................................................................................................................................ xi Conventions........................................................................................................................................... xii 1 Introductory Tutorial Overview .............................................................................................................................................. 1-1 Creating the Database Schema......................................................................................................... 1-2 Creating a New Project ...................................................................................................................... 1-3 Setting the Project’s Classpath.................................................................................................... 1-6 Enabling Your Java Classes............................................................................................................... 1-8 Generating the Class Definitions.............................................................................................. 1-10 Logging into the Database .............................................................................................................. 1-13 Creating Tables.................................................................................................................................. 1-14 Creating Tables Using the Mapping Workbench .................................................................. 1-14 Creating the Table Definitions........................................................................................... 1-14 Creating the Tables on the Database ................................................................................ 1-15 Importing Tables from the Database ....................................................................................... 1-16 Mapping Classes and Tables in the Descriptor .......................................................................... 1-18 Mappings.............................................................................................................................. 1-18 iii Descriptors............................................................................................................................ 1-18 Mapping Classes to Tables ........................................................................................................ 1-18 Preparing the Primary Keys...................................................................................................... 1-20 Setting the Sequence Table ........................................................................................................ 1-20 Implementing Direct-to-field Mappings ................................................................................. 1-22 Setting the Sequence Name ....................................................................................................... 1-23 Creating One-to-one Mappings Between Objects.................................................................. 1-25 Foreign Key References ...................................................................................................... 1-26 Creating One-to-many Mappings ............................................................................................ 1-28 Setting up Database Sessions......................................................................................................... 1-30 Logging into a Database ............................................................................................................ 1-31 Creating the Tables in Code ...................................................................................................... 1-31 Using Descriptors in an Application............................................................................................. 1-32 Transactions and Units of Work............................................................................................... 1-32 Reading and Writing Java Class Instances.............................................................................. 1-33 Using a Unit of Work to Write an Object ................................................................................ 1-34 Using a Session to Read an Object............................................................................................ 1-35 Conclusion.......................................................................................................................................... 1-37 2 Advanced Tutorial Creating the Database Schema......................................................................................................... 2-2 Creating a New Project ...................................................................................................................... 2-7 Mapping Classes to Tables .......................................................................................................... 2-8 Using the Automap Tool.................................................................................................................... 2-8 Implementing Indirection................................................................................................................. 2-9 Preparing Java Code for Indirection .......................................................................................... 2-9 Implementing Indirection in the Mapping Workbench........................................................ 2-11 Implementing Indirection in the Tutorial ............................................................................... 2-11 Implementing a One-to-one self Relationship ........................................................................... 2-12 Creating Other One-to-one Mappings..................................................................................... 2-14 Implementing a One-to-many Self-relationship ........................................................................ 2-15 Creating Other One-to-many Mappings