org.datanucleus.store.rdbms.sql.method

Class MapKeyMethod

java.lang.Object

org.datanucleus.store.rdbms.sql.method.AbstractSQLMethod

org.datanucleus.store.rdbms.sql.method.MapKeyMethod

All Implemented Interfaces:

SQLMethod

public class MapKeyMethod
extends AbstractSQLMethod

Method for evaluating KEY({mapExpr}). Returns an ObjectExpression representing the key mapping.

Field Summary

Fields inherited from class org.datanucleus.store.rdbms.sql.method.AbstractSQLMethod

clr, exprFactory, stmt

Constructor Summary

Constructors

Constructor and Description
MapKeyMethod()

Method Summary

Modifier and Type	Method and Description
protected SQLExpression	getAsJoin(MapExpression mapExpr) Implementation of KEY(mapExpr) using a join to the table representing the map, and returning an expression for the key.
protected SQLExpression	getAsSubquery(MapExpression mapExpr) Implementation of KEY(mapExpr) using a subquery on the table representing the map.
SQLExpression	getExpression(SQLExpression expr, List<SQLExpression> args) Return the expression for this SQL function.

Methods inherited from class org.datanucleus.store.rdbms.sql.method.AbstractSQLMethod

getMappingForClass, setStatement

Methods inherited from class java.lang.Object

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

Constructor Detail

MapKeyMethod

public MapKeyMethod()

Method Detail

getExpression

public SQLExpression getExpression(SQLExpression expr,
                                   List<SQLExpression> args)

Description copied from interface: SQLMethod

Return the expression for this SQL function.

Parameters:

expr - The expression that it is invoked on

args - Arguments passed in

Returns:

The SQL expression using the SQL function

getAsJoin

protected SQLExpression getAsJoin(MapExpression mapExpr)

Implementation of KEY(mapExpr) using a join to the table representing the map, and returning an expression for the key.

Parameters:

mapExpr - The map expression

Returns:

The value expression

getAsSubquery

protected SQLExpression getAsSubquery(MapExpression mapExpr)

Implementation of KEY(mapExpr) using a subquery on the table representing the map.

Parameters:

mapExpr - The map expression

Returns:

The value expression