20 Configuring a Relational Project

20.1 Introduction to Relational Project Configuration

In addition to the configurable options described here, you must also configure the base class options described in Table 117-2, "Common Project Options".

Table 20-1 lists the configurable options for relational projects.

Table 20-1 Configurable Options for Relational Projects

Option to Configure	Oracle JDeveloper	TopLink Workbench	Java
Project save location (see Section 117.2, "Configuring Project Save Location")
Persistence type (see Section 117.5, "Configuring Persistence Type")
Project classpath (see Section 117.3, "Configuring Project Classpath")
Project comments (see Section 117.14, "Configuring Project Comments")
Method or direct field access (see Section 117.4, "Configuring Method or Direct Field Access at the Project Level")
Default descriptor advanced properties (see Section 117.6, "Configuring Default Descriptor Advanced Properties")
Existence checking (see Section 117.7, "Configuring Existence Checking at the Project Level")
Project deployment XML options (see Section 117.8, "Configuring Project Deployment XML Options")
Model Java source code options (see Section 117.9, "Configuring Model Java Source Code Options")
Relational database (see Section 20.2, "Configuring Relational Database Platform at the Project Level")
Sequencing (see Section 20.3, "Configuring Sequencing at the Project Level")
Login information (see Section 20.4, "Configuring Login Information at the Project Level")
Development and deployment logins (see Section 20.5, "Configuring Development and Deployment Logins")
Cache type and size (see Section 117.10, "Configuring Cache Type and Size at the Project Level")
Cache isolation (see Section 117.11, "Configuring Cache Isolation at the Project Level")
Cache coordination change propagation (see Section 117.12, "Configuring Cache Coordination Change Propagation at the Project Level")
Cache expiration (see Section 117.13, "Configuring Cache Expiration at the Project Level")
Named query parameterized SQL and statement caching (see Section 20.7, "Configuring Named Query Parameterized SQL and Statement Caching at the Project Level")
Table generation options (see Section 20.8, "Configuring Table Generation Options")
Table creator Java source options (see Section 20.9, "Configuring Table Creator Java Source Options")
Project Java source code options (see Section 20.10, "Configuring Project Java Source Code Options")
Deprecated direct mappings (see Section 20.11, "Configuring Deprecated Direct Mappings")

For more information, see Chapter 18, "Introduction to Relational Projects".

20.2 Configuring Relational Database Platform at the Project Level

For each relational project, you must specify the database platform (such as Oracle Database 10g). This platform configuration is overridden by the session login, if configured.

For more information, see the following:

• Section 98.2, "Configuring a Relational Database Platform at the Session Level"

• Section 96.1.3, "Data Source Platform Types"

20.3 Configuring Sequencing at the Project Level

Sequencing allows TopLink to automatically assign the primary key or ID of an object when the object is inserted.

You configure TopLink sequencing at the project or session level to tell TopLink how to obtain sequence values: that is, what type of sequences to use.

In a CMP project, you do not configure a session directly: in this case, you must configure sequences at the project level. In a POJO project, you can configure a session directly: in this case, you can use a session-level sequence configuration to override project-level sequence configuration, on a session-by-session basis, if required (see Section 98.4, "Configuring Sequencing at the Session Level").

You can configure sequencing using Oracle JDeveloper.

Using TopLink Workbench (see Section 20.3.1, "How to Configure Sequencing at the Project Level Using TopLink Workbench"), you can configure table sequencing (see Section 18.2.2.1, "Table Sequencing") and native sequencing (Section 18.2.2.5, "Native Sequencing with an Oracle Database Platform" and Section 18.2.2.6, "Native Sequencing with a Non-Oracle Database Platform") and you can configure a preallocation size that applies to all sequences (see Section 18.2.3, "Sequencing and Preallocation Size").

Using Java (see Section 20.3.2, "How to Configure Sequencing at the Project Level Using Java"), you can configure any sequence type that TopLink supports (Section 18.2.2, "Sequencing Types"). You can create any number and combination of sequences. You can create a sequence object explicitly or use the default sequence that the platform creates. You can associate the same sequence with more than one descriptor and you can configure a separate preallocation size for each descriptor's sequence.

After configuring the sequence type at the project (or session) level, to enable sequencing, you must configure a descriptor with a sequence field and a sequence name (see Section 23.3, "Configuring Sequencing at the Descriptor Level").

For more information about sequencing, see Section 18.2, "Sequencing in Relational Projects".

// Enable native sequencing for the project as the default. Configured the default    
// preallocation size
project.getLogin().useNativeSequencing();
project.getLogin().setSequencePreallocationSize(50);

// Configure the EMP_SEQ to not use preallocation
DefaultSequence empSequence = new DefaultSequence("EMP_SEQ", 1);
project.getLogin().addSequence(empSequence);

// Configure the PROJ_SEQ to use a seperate sequence table
UnarySequence projSequence = new UnarySequence("PROJ_SEQ_TAB", "COUNTER");
project.getLogin().addSequence(projSequence);

20.4 Configuring Login Information at the Project Level

This section describes how to define a login to a relational database. After you define a login, you must designate its role (see Section 20.5, "Configuring Development and Deployment Logins").

After you create a login (see Section 20.4, "Configuring Login Information at the Project Level") and specify it as a development login (see Section 20.5, "Configuring Development and Deployment Logins"), you can log in to a database instance (see Section 20.6, "Logging In to the Database").

20.5 Configuring Development and Deployment Logins

This section describes how to designate a defined login's role. For information on how to define a login, see Section 20.4, "Configuring Login Information at the Project Level". TopLink recognizes the following login roles:

• Development Role

• CMP Deployment Role

• POJO Session Role

Development Role

While using TopLink Workbench to develop a project (see Section 15.2.4.3, "Development Role"), you must define a login (see Section 20.4, "Configuring Login Information at the Project Level") and designate it as the development login. The development login is stored in the TopLink project file. TopLink Workbench use the information in the development login whenever you perform a data source operation from within TopLink Workbench. For example, when you read or write schema information from or to a data source during application development, the development login information is never written to a sessions.xml or project.xml file and is overridden by the deployment login (or the session login) at run time.

For more information on how to use a development login to connect to a database, see Section 20.6, "Logging In to the Database".

CMP Deployment Role

If you are creating a CMP project (see Section 15.2.4.2, "CMP Deployment Role"), you may define a run-time login (see Section 20.4, "Configuring Login Information at the Project Level") and designate it as the deployment login. This is the login that the application will use at run time, unless overridden in the sessions.xml file, CMP deployment file, or through Java code.

POJO Session Role

If you are creating a POJO project (see Section 15.2.4.1, "POJO Session Role"), Oracle recommends that you use the sessions.xml file to store the sessions your project uses at run time (see Section 96.1.2, "Data Source Login Types").

20.6 Logging In to the Database

Using Oracle JDeveloper or TopLink Workbench, after you create a login (see Section 20.4, "Configuring Login Information at the Project Level") and specify it as a development login (see Section 20.5, "Configuring Development and Deployment Logins"), you can log in to a database instance.

You must log in to the database before importing or exporting table information.

To log in to the database using TopLink Workbench, use one of the following procedures:

• 
  Select the database object in the Navigator and click Login. TopLink Workbench logs in to the database.

• Right-click on the database object in the Navigator and choose Log In to Database from the context menu, or choose Selected > Log In to Database from the menu.

The database icon in the Navigator window changes to indicate you are now logged in to the database.

20.7 Configuring Named Query Parameterized SQL and Statement Caching at the Project Level

You can configure TopLink to use parameterized SQL (parameter binding) and prepared statement caching for all named queries and finders.

By default, TopLink uses parameterized SQL.

The use of parameterized SQL lets you create and store queries that are complete except for one or more bound parameters. The TopLink runtime binds the current parameter values when executing the query. This approach avoids the preparation of SQL execution and, thus, improves the performance of frequently executed SQL statements.

This section describes configuring parameterized SQL and statement caching options at the project level. This configuration applies to all named queries or finders (see Section 108.8, "Named Queries" or Section 108.15, "EJB 2.n CMP Finders") you create on the descriptors in this project–not to all queries in general or write operations.

You can also configure parameterized SQL and statement caching options at the named query or finder-level to override this project-level configuration on a query-by-query basis (see Section 119.7.1.9, "Configuring Named Query Options") or at the session login-level (see Section 98.6, "Configuring JDBC Options").

For more information, see Section 12.11.5, "How to Use Parameterized SQL (Parameter Binding) and Prepared Statement Caching for Optimization".

Table 20-2 summarizes which projects support parameterized SQL and statement caching configuration.

Table 20-2 Project Support for Default Named Query Caching and Binding

Descriptor	How to Use Oracle JDeveloper	How to Configure Named Query Parameterized SQL and Statement Caching at the Project Level Using TopLink Workbench	How to Use Java
Relational Projects
EIS Projects
XML Projects

20.8 Configuring Table Generation Options

Using TopLink Workbench, you can configure options that apply when you generate database tables from the descriptors you define in your TopLink Workbench project. The resulting tables and columns will conform to the naming restrictions of the project's target database.

20.9 Configuring Table Creator Java Source Options

Using TopLink Workbench, you can configure options that apply when you export Java source code that you can use to create database tables.

20.10 Configuring Project Java Source Code Options

Using TopLink Workbench, you can export a project as Java source. You can configure the class name and root directory that TopLink Workbench uses when exporting the project to Java source code.

For more information on exporting a project as Java source, see Section 19.6.1, "How to Export Project Java Source Using TopLink Workbench".

20.11 Configuring Deprecated Direct Mappings

You can configure deprecated direct mapping options when using Oracle JDeveloper or TopLink Workbench.

Starting with the 10.1.3.1 release, TopLink no longer uses the following direct mapping types:

• Type conversion

• Object type

• Serialized object

Instead, TopLink uses a direct-to-field mapping with a specialized converter.

To generate backward-compatible deployment XML and Java source code files, use the Generate Deprecated Direct Mappings option.