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NvlFunction (Hibernate API Documentation) - Hibernate 3.2.3 正式版 API 英文文档

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org.hibernate.dialect.function
Class NvlFunction

java.lang.Object
  org.hibernate.dialect.function.NvlFunction

All Implemented Interfaces:

SQLFunction

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public class NvlFunction

extends Object

implements SQLFunction

Emulation of coalesce() on Oracle, using multiple nvl() calls

Author:

Gavin King

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Constructor Summary

NvlFunction()

 

Method Summary
Type	getReturnType(Type columnType, Mapping mapping)           The return type of the function.
boolean	hasArguments()           Does this function have any arguments?
boolean	hasParenthesesIfNoArguments()           If there are no arguments, are parens required?
String	render(List args, SessionFactoryImplementor factory)           Render the function call as SQL fragment.

 

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Constructor Detail

NvlFunction

public NvlFunction()

Method Detail

getReturnType

public Type getReturnType(Type columnType,
                          Mapping mapping)
                   throws QueryException

Description copied from interface: SQLFunction

The return type of the function. May be either a concrete type which is preset, or variable depending upon the type of the first function argument.

Specified by:

getReturnType in interface SQLFunction

Parameters:

columnType - the type of the first argument

mapping - The mapping source.

Returns:

The type to be expected as a return.

Throws:

QueryException - Indicates an issue resolving the return type.

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hasArguments

public boolean hasArguments()

Description copied from interface: SQLFunction

Does this function have any arguments?

Specified by:

hasArguments in interface SQLFunction

Returns:

True if the function expects to have parameters; false otherwise.

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hasParenthesesIfNoArguments

public boolean hasParenthesesIfNoArguments()

Description copied from interface: SQLFunction

If there are no arguments, are parens required?

Specified by:

hasParenthesesIfNoArguments in interface SQLFunction

Returns:

True if a no-arg call of this function requires parentheses.

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render

public String render(List args,
                     SessionFactoryImplementor factory)
              throws QueryException

Description copied from interface: SQLFunction

Render the function call as SQL fragment.

Specified by:

render in interface SQLFunction

Parameters:

args - The function arguments

factory - The SessionFactory

Returns:

The rendered function call

Throws:

QueryException - Indicates a problem rendering the function call.

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