org.datanucleus.store.rdbms.sql.method
Class ArraySizeMethod

java.lang.Object
  org.datanucleus.store.rdbms.sql.method.AbstractSQLMethod
      org.datanucleus.store.rdbms.sql.method.ArraySizeMethod

All Implemented Interfaces:

SQLMethod

public class ArraySizeMethod
extends AbstractSQLMethod

Method for evaluating {arrExpr1}.size(). Returns a NumericExpression. Equates to a sub-query on the table for the array returning the COUNT(*) of the number of elements. Something like

 SELECT COUNT(*) FROM ARRTABLE A0_SUB WHERE A0_SUB.OWNER_ID_OID = A0.OWNER_ID
 

where A0 is the candidate table in the outer query, and ARRTABLE is the join table (if using join collection) or the element table (if using FK array).

Field Summary

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

clr, exprFactory, LOCALISER, stmt

Constructor Summary

ArraySizeMethod()

Method Summary

SQLExpression

getExpression(SQLExpression expr, java.util.List 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

ArraySizeMethod

public ArraySizeMethod()

Method Detail

getExpression

public SQLExpression getExpression(SQLExpression expr,
                                   java.util.List 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