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public interface DBQuery
Utility for querying object from a database. Allocates connections from the database connection pool, ensures the integrity of those connections, and manages result sets after a query is performed. Returns objects representing data in the database.
Example - querying a user:
import org.enhydra.dods.DODS; import com.lutris.appserver.server.sql.*; DBQuery dbQuery = DODS.getDatabaseManager().createQuery(DATABASE_NAME); // NOTE: class CustomerQuery implements Query { ... } CustomerQuery customerQuery = new CustomerQuery(); String [] loginIds = { "customer1", "customer2" }; try { for (int idx=0; idx < loginIds.length; idx++) { customerQuery.setQueryLoginId(loginIds[idx]); dbQuery.query(customerQuery); // query the database // Print all query results. CustomerDO customerResult; while ((customerResult = (CustomerDO)dbQuery.next()) != null) { System.out.println("Customer name for " + loginIds[idx] + " is " + customerResult.getName()); } } } finally { // // Return database connections used by // this object back to the connection pool // and free any other resources consumed // by this object. // dbQuery.release(); }
Method Summary | |
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boolean |
handleException(java.sql.SQLException e)
Exception handler. |
java.lang.Object |
next()
Returns a new object representing the next result form the query. |
void |
query(Query q)
Query the database. |
void |
release()
Frees all resources consumed by this query. |
void |
validate()
Method to ensure this object is still valid. |
Method Detail |
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void query(Query q) throws java.sql.SQLException
q
- Query interface via which the query will be executed.
java.sql.SQLException
- If a database access error occurs.java.lang.Object next() throws java.sql.SQLException, ObjectIdException
java.sql.SQLException
- If a database access error occurs.
ObjectIdException
- If ObjectId was not found.void release()
boolean handleException(java.sql.SQLException e)
void validate() throws java.sql.SQLException
java.sql.SQLException
- If a database access error occurs.
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