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

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

All Implemented Interfaces:

SQLMethod

public class ArrayContainsMethod
extends AbstractSQLMethod

Method for evaluating {arrExpr}.contains(elemExpr). Returns a BooleanExpression.

Field Summary

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

clr, exprFactory, LOCALISER, stmt

Constructor Summary

ArrayContainsMethod()

Method Summary

protected SQLExpression	containsAsSubquery(ArrayExpression arrExpr, SQLExpression elemExpr) Method to return an expression for Collection.contains using a subquery "EXISTS".
SQLExpression	getExpression(SQLExpression expr, 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

ArrayContainsMethod

public ArrayContainsMethod()

Method Detail

getExpression

public SQLExpression getExpression(SQLExpression expr,
                                   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

containsAsSubquery

protected SQLExpression containsAsSubquery(ArrayExpression arrExpr,
                                           SQLExpression elemExpr)

Method to return an expression for Collection.contains using a subquery "EXISTS". This is for use when there are "!contains" or "OR" operations in the filter. Creates the following SQL,

• Collection of NonPC using join table

   SELECT 1 FROM JOIN_TBL A0_SUB 
   WHERE A0_SUB.JOIN_OWN_ID = A0.ID AND A0_SUB.JOIN_ELEM_ID = {elemExpr}
   

• Collection of PC using join table

   SELECT 1 FROM ELEM_TABLE A0_SUB INNER JOIN JOIN_TBL B0 ON ... 
   WHERE B0.JOIN_OWN_ID = A0.ID AND A0_SUB.ID = {elemExpr}
   

and returns a BooleanSubqueryExpression ("EXISTS (subquery)")

Parameters:

arrExpr - Collection expression

elemExpr - Expression for the element

Returns:

Contains expression