Changes for page The EOModel

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25	25	■ define derived attributes
26	26	■ build database queries in raw SQL
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28		-In an Entity-Relationship model, distinguishable things are known as entities, each entity is defined by its component attributes, and the affiliations, or relationships between entities, are identified (together, attributes and relationships are known as properties). From these three simple modeling objects~-~--entities, attributes, and relationships~-~--arbitrarily complex systems can be modeled.
	28	+In an Entity-Relationship model, distinguishable things are known as entities, each entity is defined by its component attributes, and the affiliations, or relationships between entities, are identified (together, attributes and relationships are known as properties). From these three simple modeling objects~-~-entities, attributes, and relationships~-~-arbitrarily complex systems can be modeled.
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30	30	== Entities ==
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114	114	~1. An entity named EOAdaptorNamePrototypes, where AdaptorName is the name of the adaptor for your model. WebObjects 5.2 includes an adaptor for JDBC data sources and an adaptor for JNDI data sources. So you can create a prototype entity called either EOJDBCPrototypes or EOJNDIPrototypes, depending on the adaptor you use.
115	115	2. An entity named EOPrototypes.
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117		-To create a prototype attribute, first create a prototype entity~-~--an entity named either EOAdaptorNamePrototypes or EOPrototypes~-~--and add an attribute to it. Figure 3-3 shows an attribute in a prototype entity. It shows all the values that prototype attributes can define: column name, value class, external type, and value type.
	117	+To create a prototype attribute, first create a prototype entity~-~-an entity named either EOAdaptorNamePrototypes or EOPrototypes~-~-and add an attribute to it. Figure 3-3 shows an attribute in a prototype entity. It shows all the values that prototype attributes can define: column name, value class, external type, and value type.
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119	119	To assign a prototype attribute to an attribute, reveal the Prototype column in table mode, and select a prototype attribute from the pop-up menu. The prototype attributes that appear in the pop-up list in the Prototype column include prototype attributes defined in any entity in any model in the application's model group, which includes the current model.
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274	274	== EO Inheritance ==
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276		-One of the issues that may arise in designing your enterprise objects~-~--whether you're creating a schema from scratch or working with an existing database schema~-~--is the modeling of inheritance relationships.
	276	+One of the issues that may arise in designing your enterprise objects~-~-whether you're creating a schema from scratch or working with an existing database schema~-~-is the modeling of inheritance relationships.
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278	278	In object-oriented programming, it's natural to think of data in terms of inheritance. A Customer object, for example, naturally inherits certain characteristics from a Person object, such as name, address, and phone number. In inheritance hierarchies, the parent object or superclass is usually rather generic so that less generic subclasses of a related type can easily be added. So, in addition to the Customer object, a Client object also naturally derives from a Person object.
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336	336	Single-table mapping results in tables that have columns for all of the attributes of each entity in the inheritance hierarchy. It also results in many null row values. While these aren't really disadvantages, they may conflict with some database design philosophies.
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	338	+=== Using Inheritance in Entity Modeler ===
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	340	+To use Inheritance in your model, you first need to create your base entity. When done, right-click on the entity and select Subclass. A dialog will appear and will ask you to specify which kind of Inheritance you want to use, which entity is the parent and the name of the new (child) entity. When selecting Vertical or Single-Table Inheritance, you can also specify the qualifier (type = XX) in that dialog (you can do that part later too).
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338	338	== EOGenerator ==
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340	340	== Handling Blob Data ==