public class DerbyConcatFunction extends Object implements SQLFunction
A specialized concat() function definition in which:<ol> <li>we translate to use the concat operator ('||')</li> <li>wrap dynamic parameters in CASTs to VARCHAR</li> </ol> <p/> This last spec is to deal with a limitation on DB2 and variants (e.g. Derby) where dynamic parameters cannot be used in concatenation unless they are being concatenated with at least one non-dynamic operand. And even then, the rules are so convoluted as to what is allowed and when the CAST is needed and when it is not that we just go ahead and do the CASTing.
Constructor and Description |
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DerbyConcatFunction() |
Modifier and Type | Method and Description |
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Type |
getReturnType(Type argumentType,
Mapping mapping)
The return type of the function.
|
boolean |
hasArguments()
Does this function have any arguments?
|
boolean |
hasParenthesesIfNoArguments()
If there are no arguments, are parentheses required?
|
String |
render(Type argumentType,
List args,
SessionFactoryImplementor factory)
Render the function call as SQL fragment.
|
public boolean hasArguments()
Does this function have any arguments?
<p/> Here we always return <tt>true</tt>hasArguments
in interface SQLFunction
public boolean hasParenthesesIfNoArguments()
If there are no arguments, are parentheses required?
<p/> Here we always return <tt>true</tt>hasParenthesesIfNoArguments
in interface SQLFunction
public Type getReturnType(Type argumentType, Mapping mapping) throws QueryException
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.
<p/>
Note, the 'firstArgumentType' parameter should match the one passed into SQLFunction.render(org.hibernate.type.Type, java.util.List, org.hibernate.engine.spi.SessionFactoryImplementor)
StandardBasicTypes.STRING
.getReturnType
in interface SQLFunction
argumentType
- The type of the first argumentmapping
- The mapping source.QueryException
- Indicates an issue resolving the return type.public String render(Type argumentType, List args, SessionFactoryImplementor factory) throws QueryException
Render the function call as SQL fragment.
<p/>
Note, the 'firstArgumentType' parameter should match the one passed into SQLFunction.getReturnType(org.hibernate.type.Type, org.hibernate.engine.spi.Mapping)
render
in interface SQLFunction
argumentType
- The type of the first argumentargs
- The function argumentsfactory
- The SessionFactoryQueryException
- Indicates a problem rendering the
function call.Copyright © 2001-2018 Red Hat, Inc. All Rights Reserved.