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Configuring an Object-Relational Data Type Mapping (ELUG)
Contents
This section describes how to configure an object-relational data type mapping.
For information on how to configure EclipseLink mappings options common to two or more mapping types, see Configuring a Mapping.
For information on how to create EclipseLink mappings, see Creating a Mapping (ELUG)#Creating a Mapping.
Introduction to Object-Relational Data Type Mapping Configuration
This table lists the types of object-relational data type mappings that you can configure and provides a cross-reference to the type-specific chapter that lists the configurable options supported by that type.
Configuring Object-Relational Data Type Mappings
| If you are creating... | See Also... |
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Object-relational data type structure mapping (see [Introduction%20to%20Object-Relational%20Data%20Type%20Mappings%20(ELUG)#Object-Relational Data Type Structure Mapping]) |
[Configuring%20an%20Object-Relational%20Data%20Type%20Structure%20Mapping%20(ELUG)#Chapter 46, "Configuring an Object-Relational Data Type Structure Mapping"] |
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[Configuring%20an%20Object-Relational%20Data%20Type%20Reference%20Mapping%20(ELUG)#Chapter 47, "Configuring an Object-Relational Data Type Reference Mapping"] | |
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[Configuring%20an%20Object-Relational%20Data%20Type%20Array%20Mapping%20(ELUG)#Chapter 48, "Configuring an Object-Relational Data Type Array Mapping"] | |
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[Configuring%20an%20Object-Relational%20Data%20Type%20Object%20Array%20Mapping%20(ELUG)#Chapter 49, "Configuring an Object-Relational Data Type Object Array Mapping"] | |
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[Configuring%20an%20Object-Relational%20Data%20Type%20Nested%20Table%20Mapping%20(ELUG)#Chapter 51, "Configuring an Object-Relational Data Type Nested Table Mapping"] |
For more information, see the following:
- [Introduction%20to%20Mappings%20(ELUG)#Chapter 16, "Introduction to Mappings"]
- [Introduction%20to%20Relational%20Mappings%20(ELUG)#Chapter 32, "Introduction to Relational Mappings"]
Configuring Common Object-Relational Data Type Mapping Options
[[#Table 50-2] lists the configurable options shared by two or more object-relational data type mapping types. In addition to the configurable options described here, you must also configure the options described for the specific object-relational data type mapping types (see [Introduction%20to%20Object-Relational%20Data%20Type%20Mappings%20(ELUG)#Object-Relational Data Type Mapping Types]), as shown in [[#Table 50-1].
Table 50-2 Common Options for Object-Relational Data Type Mappings
| Option to Configure | JDeveloper |
Workbench |
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Reference class (see [[#Configuring Reference Class]) |
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Attribute name (see [[#Configuring Attribute Name]) |
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Field name (see [[#Configuring Field Name]) |
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Structure name (see [[#Configuring Structure Name]) |
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Read-only (see [Configuring%20a%20Mapping%20(ELUG)#Configuring Read-Only Mappings]) |
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Method or direct field access (see [Configuring%20a%20Mapping%20(ELUG)#Configuring Method or Direct Field Accessing at the Mapping Level]) |
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Indirection (lazy loading) (see [Configuring%20a%20Mapping%20(ELUG)#Configuring Indirection (Lazy Loading)]) |
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Container policy (see [Configuring%20a%20Mapping%20(ELUG)#Configuring Container Policy]) |
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Configuring Reference Class
When mapping an attribute that involves a relationship to another class, you must specify the reference class–the Java class to which the mapped attribute refers.
[[#Table 50-3] summarizes which object-relational data type mappings support this option.
Table 50-3 Mapping Support for Reference Class
| Mapping | How to Use Workbench | [[#How to Configure Reference Class Using Java] |
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Object-relational data type structure mapping (see [Introduction%20to%20Object-Relational%20Data%20Type%20Mappings%20(ELUG)#Object-Relational Data Type Structure Mapping]) |
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How to Configure Reference Class Using Java
Use org.eclipse.persistence.mappings.ForeignReferenceMapping method setReferenceClass to specify the target class of the attribute being mapped.
[[#Example 50-1] shows how to use this method with a ReferenceMapping that maps the manager attribute of the Employee class.
Example 50-1 Configuring Reference Class in Java
public void customize(ClassDescriptor descriptor) {
ReferenceMapping managerMapping = new ReferenceMapping();
managerMapping.setReferenceClass("Employee.class"); // set reference class
managerMapping.setAttributeName("manager");
// add this mapping to descriptor
descriptor.addMapping (managerMapping);
}
For more information, see the EclipseLink API Reference.
Configuring Attribute Name
All object-relational data type mappings map an attribute in a Java object to field in the database. The attribute name is the name of the attribute being mapped. The name is as specified in the reference class (see [[#Configuring Reference Class]).
[[#Table 50-4] summarizes which object-relational data type mappings support this option.
Table 50-4 Mapping Support for Attribute Name
| Mapping | How to Use Workbench | [[#How to Configure Attribute Name Using Java] |
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Object-relational data type structure mapping (see [Introduction%20to%20Object-Relational%20Data%20Type%20Mappings%20(ELUG)#Object-Relational Data Type Structure Mapping]) |
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How to Configure Attribute Name Using Java
Use org.eclipse.persistence.mappings.DatabaseMapping method setAttributeName to specify the name of the attribute being mapped.
[[#Example 50-2] shows how to use this method with a ReferenceMapping that maps the manager attribute of the Employee class.
Example 50-2 Configuring Attribute Name in Java
public void customize(ClassDescriptor descriptor) {
ReferenceMapping managerMapping = new new ReferenceMapping();
managerMapping.setReferenceClass("Employee.class");
managerMapping.setAttributeName("manager"); // set attribute name
// add this mapping to descriptor
descriptor.addMapping (managerMapping);
}
For more information, see the EclipseLink API Reference.
Configuring Field Name
All object-relational data type mappings require the name of database field to which their specified attribute is mapped. This field name can be the column name of a database table or the name of a field in an object type created on the database.
[[#Table 50-5] summarizes which object-relational data type mappings support this option.
Table 50-5 Mapping Support for Field Name
| Mapping | How to Use Workbench | [[#How to Configure Field Name Using Java] |
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Object-relational data type structure mapping (see [Introduction%20to%20Object-Relational%20Data%20Type%20Mappings%20(ELUG)#Object-Relational Data Type Structure Mapping]) |
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How to Configure Field Name Using Java
Use the object-relational data type mapping method setFieldName to specify the database field to which the attribute is mapped.
[[#Example 50-3] shows how to use this method with an ObjectArrayMapping that maps the Employee class attribute phone to database field name PHONE_NUMBER.
Example 50-3 Configuring Field Name in Java
public void customize(ClassDescriptor descriptor) {
ObjectArrayMapping phonesMapping = new ObjectArrayMapping();
phonesMapping.setReferenceClass("Employee.class");
phonesMapping.setAttributeName("phone");
phonesMapping.setFieldName("PHONE_NUMBER"); // set field name
// add this mapping to descriptor
descriptor.addMapping (phonesMapping);
}
For more information, see the EclipseLink API Reference.
Configuring Structure Name
Certain object-relational data type mappings require the specification of the data type or structure name of the field being mapped. The structure name is the name of the array or table type that defines the field.
[[#Table 50-6] summarizes which object-relational data type mappings support this option.
Table 50-6 Mapping Support for Structure Name
| Mapping | How to Use JDeveloper | How to Use Workbench | [[#How to Configure Structure Name Using Java] |
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Object-relational data type structure mapping (see [Introduction%20to%20Object-Relational%20Data%20Type%20Mappings%20(ELUG)#Object-Relational Data Type Structure Mapping]) |
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How to Configure Structure Name Using Java
Use the object-relational data type mapping method setStructureName to specify the structure of the attribute being mapped.
This example shows how to use this method with an ObjectArrayMapping that maps the Employee class attribute phones to database field name PHONE_NUMBERS of type PHONE_ARRAY_TYPE.
Configuring Structure Name in Java
public void customize(ClassDescriptor descriptor) {
ObjectArrayMapping phonesMapping = new ObjectArrayMapping();
phonesMapping.setReferenceClass("Employee.class");
phonesMapping.setAttributeName("phones");
phonesMapping.setFieldName("PHONE_NUMBERS");
phonesMapping.setStructureName("PHONE_ARRAY_TYPE"); // set structure name
// add this mapping to descriptor
descriptor.addMapping (phonesMapping);
}
For more information, see the EclipseLink API Reference.