Package org.datanucleus.store.rdbms.sql.method

Class ArrayContainsMethod

java.lang.Object

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

All Implemented Interfaces:

SQLMethod

public class ArrayContainsMethod
extends Object
implements SQLMethod

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

Constructor Summary

Constructors

Constructor	Description
ArrayContainsMethod()

Method Summary

Modifier and Type	Method	Description
protected SQLExpression	containsAsSubquery(SQLStatement stmt, ArrayExpression arrExpr, SQLExpression elemExpr)	Method to return an expression for Collection.contains using a subquery "EXISTS".
protected boolean	elementTypeCompatible(Class elementType, Class collectionElementType)
SQLExpression	getExpression(SQLStatement stmt, SQLExpression expr, List<SQLExpression> args)	Return the expression for this SQL function.

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(SQLStatement stmt,
                                   SQLExpression expr,
                                   List<SQLExpression> args)

Description copied from interface: SQLMethod

Return the expression for this SQL function.

Specified by:

getExpression in interface SQLMethod

Parameters:

stmt - SQLStatement that this expression is for

expr - The expression that it is invoked on

args - Arguments passed in

Returns:

The SQL expression using the SQL function

containsAsSubquery

protected SQLExpression containsAsSubquery(SQLStatement stmt,
                                           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:

stmt - SQLStatement

arrExpr - Collection expression

elemExpr - Expression for the element

Returns:

Contains expression

elementTypeCompatible

protected boolean elementTypeCompatible(Class elementType,
                                        Class collectionElementType)