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The Java EE 5 Tutorial (PDF) - Oracle Software Downloads

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Enterprise Beans<br />

1054<br />

TABLE 37–1 Helper Classes for the Application’s Enterprise Beans (Continued)<br />

Class Name Description<br />

Debug Has simple methods for printing a debugging message from an enterprise bean.<br />

<strong>The</strong>se messages appear on the standard output of the Application Server when it’s<br />

run with the --verbose option and in the server log.<br />

DomainUtil Contains validation methods: getAccountTypes, checkAccountType, and<br />

isCreditAccount.<br />

TxDetails Encapsulates the state of a Tx instance. Returned by the getDetails method of<br />

TxControllerBean.<br />

DatabaseTables<br />

A database table of the Duke’s Bank application can be categorized by its purpose: representing<br />

business entities.<br />

Tables Representing Business Entities<br />

Figure 37–2 shows the relationships between the database tables. <strong>The</strong> bank_customer and<br />

bank_account tables have a many-to-many relationship: A customer can have several bank<br />

accounts, and each account can be owned by more than one customer. This many-to-many<br />

relationship is implemented by the cross–reference table named<br />

bank_customer_account_xref. <strong>The</strong> tables named bank_account and bank_tx have a<br />

one-to-many relationship: A bank account can have many transactions, but each transaction<br />

refers to a single account.<br />

<strong>The</strong> <strong>Java</strong> <strong>EE</strong> 5<strong>Tutorial</strong> • June 2010

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