Index: TECH/Algo/SQL/QueryEngine/EnkelvoudigeConditie.cls.xml
===================================================================
diff -u
--- TECH/Algo/SQL/QueryEngine/EnkelvoudigeConditie.cls.xml	(revision 0)
+++ TECH/Algo/SQL/QueryEngine/EnkelvoudigeConditie.cls.xml	(revision 3044)
@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Export generator="Cache" version="9">
+<Class name="TECH.Algo.SQL.QueryEngine.EnkelvoudigeConditie">
+<ProcedureBlock>1</ProcedureBlock>
+<Super>%RegisteredObject,TECH.Algo.SQL.QueryEngine.IWhereConditie</Super>
+<ClassDefinitionError>0</ClassDefinitionError>
+
+<Property name="ConditieString">
+<Type>%String</Type>
+<Private>1</Private>
+</Property>
+
+<Method name="%OnNew">
+<FormalSpec>ConditieString:%String</FormalSpec>
+<Private>1</Private>
+<ProcedureBlock>1</ProcedureBlock>
+<ReturnType>%Status</ReturnType>
+<Implementation><![CDATA[
+	Set ..ConditieString = ConditieString
+	Quit $$$OK
+]]></Implementation>
+</Method>
+
+<Method name="MaakConditieString">
+<ReturnType>%String</ReturnType>
+<Implementation><![CDATA[	Quit ..ConditieString
+]]></Implementation>
+</Method>
+
+<Method name="VoegToeKind">
+<FormalSpec>Kindknoop:TECH.Algo.Boom.Knoop</FormalSpec>
+<Implementation><![CDATA[	Do ##class(TECH.ExceptionHandler).Throw(##class(TECH.Exceptions.InvalidInputException).%New("Er zijn geen kinderen op deze bladknoop"))
+]]></Implementation>
+</Method>
+
+<Method name="GeefKindIterator">
+<ReturnType>TECH.Iterator</ReturnType>
+<Implementation><![CDATA[	Do ##class(TECH.ExceptionHandler).Throw(##class(TECH.Exceptions.InvalidInputException).%New("Er zijn geen kinderen op deze bladknoop"))
+]]></Implementation>
+</Method>
+</Class>
+</Export>
Index: vhUnitTest/TECH/Algo/SQL/QueryEngine/TestQueryEngine.cls.xml
===================================================================
diff -u -r3020 -r3044
--- vhUnitTest/TECH/Algo/SQL/QueryEngine/TestQueryEngine.cls.xml	(.../TestQueryEngine.cls.xml)	(revision 3020)
+++ vhUnitTest/TECH/Algo/SQL/QueryEngine/TestQueryEngine.cls.xml	(.../TestQueryEngine.cls.xml)	(revision 3044)
@@ -7,11 +7,45 @@
 <Super>vhUnitTest.TestCase</Super>
 <ClassDefinitionError>0</ClassDefinitionError>
 
-<Method name="TestQueryBuilder">
+<Method name="TestEenvoudigeSelectie">
 <Implementation><![CDATA[
 	Set QueryBuilder = ##class(TECH.Algo.SQL.QueryEngine.QueryBuilder).%New()
 	
 	Set TabelA = ##class(TECH.Algo.SQL.QueryEngine.Tabel).%New("TabelA")
+	Do QueryBuilder.VoegToeTabel(TabelA)
+	Do QueryBuilder.SelecteerVeldVanTabel("VeldA",TabelA)
+	
+	Do $$$AssertEquals(QueryBuilder.GeefQueryString(),"SELECT TabelA.VeldA FROM TabelA","De query string")
+]]></Implementation>
+</Method>
+
+<Method name="TestWhereConditie">
+<Implementation><![CDATA[
+	Set QueryBuilder = ##class(TECH.Algo.SQL.QueryEngine.QueryBuilder).%New()
+	
+	Set TabelA = ##class(TECH.Algo.SQL.QueryEngine.Tabel).%New("TabelA")
+	Do QueryBuilder.VoegToeTabel(TabelA)
+	Do QueryBuilder.SelecteerVeldVanTabel("VeldA",TabelA)
+	
+	Set WhereConditie = ##class(TECH.Algo.SQL.QueryEngine.CombinatieConditie).%New(##class(TECH.Algo.SQL.QueryEngine.enu.CombinatieConditieOperator).En())
+	Do WhereConditie.VoegToeSubconditie(##class(TECH.Algo.SQL.QueryEngine.EnkelvoudigeConditie).%New("TabelA.VeldA = 'IetsA'"))
+	Set CombinatieConditie = ##class(TECH.Algo.SQL.QueryEngine.CombinatieConditie).%New(##class(TECH.Algo.SQL.QueryEngine.enu.CombinatieConditieOperator).Of())
+	Do CombinatieConditie.VoegToeSubconditie(##class(TECH.Algo.SQL.QueryEngine.EnkelvoudigeConditie).%New("TabelA.VeldB = 'IetsB'"))
+	Do CombinatieConditie.VoegToeSubconditie(##class(TECH.Algo.SQL.QueryEngine.EnkelvoudigeConditie).%New("TabelA.VeldC = 'IetsC'"))
+	Do WhereConditie.VoegToeSubconditie(CombinatieConditie)
+	Do WhereConditie.VoegToeSubconditie(##class(TECH.Algo.SQL.QueryEngine.EnkelvoudigeConditie).%New("TabelA.VeldD = 'IetsD'"))
+	
+	Do QueryBuilder.ZetWhereConditie(WhereConditie)
+	
+	Do $$$AssertEquals(QueryBuilder.GeefQueryString(),"SELECT TabelA.VeldA FROM TabelA WHERE (TabelA.VeldA = 'IetsA' AND (TabelA.VeldB = 'IetsB' OR TabelA.VeldC = 'IetsC') AND TabelA.VeldD = 'IetsD')","De query string")
+]]></Implementation>
+</Method>
+
+<Method name="TestJoinMeervoudigeParams">
+<Implementation><![CDATA[
+	Set QueryBuilder = ##class(TECH.Algo.SQL.QueryEngine.QueryBuilder).%New()
+	
+	Set TabelA = ##class(TECH.Algo.SQL.QueryEngine.Tabel).%New("TabelA")
 	Set TabelB = ##class(TECH.Algo.SQL.QueryEngine.Tabel).%New("TabelB")
 	
 	Do QueryBuilder.VoegToeTabel(TabelA)
@@ -20,13 +54,40 @@
 	Do QueryBuilder.SelecteerVeldVanTabel("VeldA",TabelA)
 	Do QueryBuilder.SelecteerVeldVanTabel("VeldB",TabelB)
 	
-	Set ForeignKey = ##class(TECH.Algo.SQL.QueryEngine.ForeignKey).%New("VeldA", TabelA, "VeldB", TabelB)
+	Set ForeignKey = ##class(TECH.Algo.SQL.QueryEngine.ForeignKey).%New("VeldB", TabelB, "VeldA", TabelA)
 	Do QueryBuilder.VoegToeForeignKey(ForeignKey)
-	Set ForeignKey = ##class(TECH.Algo.SQL.QueryEngine.ForeignKey).%New("VeldB", TabelA, "VeldC", TabelB)
+	Set ForeignKey = ##class(TECH.Algo.SQL.QueryEngine.ForeignKey).%New("VeldC", TabelB, "VeldB", TabelA)
 	Do QueryBuilder.VoegToeForeignKey(ForeignKey)
 	
-	Do $$$AssertEquals(QueryBuilder.GeefQueryString(),"SELECT TabelA.VeldA, TabelB.VeldB JOIN TabelB ON TabelA.VeldA = TabelB.VeldB AND TabelA.VeldB = TabelB.VeldC FROM TabelA","De query string")
+	Do $$$AssertEquals(QueryBuilder.GeefQueryString(),"SELECT TabelA.VeldA, TabelB.VeldB FROM TabelA JOIN TabelB ON TabelB.VeldB = TabelA.VeldA AND TabelB.VeldC = TabelA.VeldB","De query string")
 ]]></Implementation>
 </Method>
+
+<Method name="TestMeervoudigeJoin">
+<Implementation><![CDATA[
+	Set QueryBuilder = ##class(TECH.Algo.SQL.QueryEngine.QueryBuilder).%New()
+	
+	Set TabelA = ##class(TECH.Algo.SQL.QueryEngine.Tabel).%New("TabelA")
+	Set TabelB = ##class(TECH.Algo.SQL.QueryEngine.Tabel).%New("TabelB")
+	Set TabelC = ##class(TECH.Algo.SQL.QueryEngine.Tabel).%New("TabelC")
+	
+	Do QueryBuilder.VoegToeTabel(TabelA)
+	Do QueryBuilder.VoegToeTabel(TabelB)
+	Do QueryBuilder.VoegToeTabel(TabelC)
+	
+	Do QueryBuilder.SelecteerVeldVanTabel("VeldA",TabelA)
+	Do QueryBuilder.SelecteerVeldVanTabel("VeldB",TabelB)
+	Do QueryBuilder.SelecteerVeldVanTabel("VeldC",TabelC)
+	
+	Set ForeignKey = ##class(TECH.Algo.SQL.QueryEngine.ForeignKey).%New("VeldB", TabelB, "VeldA", TabelA)
+	Do QueryBuilder.VoegToeForeignKey(ForeignKey)
+	Set ForeignKey = ##class(TECH.Algo.SQL.QueryEngine.ForeignKey).%New("VeldC", TabelB, "VeldB", TabelA)
+	Do QueryBuilder.VoegToeForeignKey(ForeignKey)
+	Set ForeignKey = ##class(TECH.Algo.SQL.QueryEngine.ForeignKey).%New("VeldD", TabelC, "VeldA", TabelA)
+	Do QueryBuilder.VoegToeForeignKey(ForeignKey)
+	
+	Do $$$AssertEquals(QueryBuilder.GeefQueryString(),"SELECT TabelA.VeldA, TabelB.VeldB, TabelC.VeldC FROM TabelA JOIN TabelB ON TabelB.VeldB = TabelA.VeldA AND TabelB.VeldC = TabelA.VeldB JOIN TabelC ON TabelC.VeldD = TabelA.VeldA","De query string")
+]]></Implementation>
+</Method>
 </Class>
 </Export>
Index: vhUnitTest/TECH/Algo/Boom/impl/Knoop.cls.xml
===================================================================
diff -u -r3019 -r3044
--- vhUnitTest/TECH/Algo/Boom/impl/Knoop.cls.xml	(.../Knoop.cls.xml)	(revision 3019)
+++ vhUnitTest/TECH/Algo/Boom/impl/Knoop.cls.xml	(.../Knoop.cls.xml)	(revision 3044)
@@ -16,7 +16,7 @@
 ]]></Implementation>
 </Method>
 
-<Method name="GeefKinderenIterator">
+<Method name="GeefKindIterator">
 <ReturnType>TECH.Iterator</ReturnType>
 <Implementation><![CDATA[	Quit ##class(TECH.ListIterator).%New(..Kinderen)
 ]]></Implementation>
Index: TECH/Algo/SQL/QueryEngine/CombinatieConditie.cls.xml
===================================================================
diff -u
--- TECH/Algo/SQL/QueryEngine/CombinatieConditie.cls.xml	(revision 0)
+++ TECH/Algo/SQL/QueryEngine/CombinatieConditie.cls.xml	(revision 3044)
@@ -0,0 +1,62 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Export generator="Cache" version="9">
+<Class name="TECH.Algo.SQL.QueryEngine.CombinatieConditie">
+<ProcedureBlock>1</ProcedureBlock>
+<Super>%RegisteredObject,TECH.Algo.SQL.QueryEngine.IWhereConditie</Super>
+<ClassDefinitionError>0</ClassDefinitionError>
+
+<Property name="CombinatieConditieOperator">
+<Type>TECH.Algo.SQL.QueryEngine.enu.CombinatieConditieOperator</Type>
+<Private>1</Private>
+</Property>
+
+<Property name="Subcondities">
+<Type>TECH.Algo.SQL.QueryEngine.IWhereConditie</Type>
+<Collection>list</Collection>
+</Property>
+
+<Method name="%OnNew">
+<FormalSpec>CombinatieConditieOperator:TECH.Algo.SQL.QueryEngine.enu.CombinatieConditieOperator</FormalSpec>
+<Private>1</Private>
+<ProcedureBlock>1</ProcedureBlock>
+<ReturnType>%Status</ReturnType>
+<Implementation><![CDATA[
+	Set ..CombinatieConditieOperator = CombinatieConditieOperator
+	Quit $$$OK
+]]></Implementation>
+</Method>
+
+<Method name="VoegToeSubconditie">
+<FormalSpec>Subconditie:TECH.Algo.SQL.QueryEngine.IWhereConditie</FormalSpec>
+<Implementation><![CDATA[	Do ..Subcondities.Insert(Subconditie)
+]]></Implementation>
+</Method>
+
+<Method name="MaakConditieString">
+<ReturnType>%String</ReturnType>
+<Implementation><![CDATA[
+	Set Conditie = ""
+	Set SubconditiesIterator = ##class(TECH.ListIterator).%New(..Subcondities)
+	While (SubconditiesIterator.HasNext())
+	{
+		Set Subconditie = SubconditiesIterator.Next()
+		Set Conditie = Conditie_Subconditie.MaakConditieString()
+		If (SubconditiesIterator.HasNext()) { Set Conditie = Conditie_" "_..CombinatieConditieOperator_" " }
+	}
+	Quit "("_Conditie_")"
+]]></Implementation>
+</Method>
+
+<Method name="GeefKindIterator">
+<ReturnType>TECH.Iterator</ReturnType>
+<Implementation><![CDATA[	Quit ##class(TECH.ListIterator).%New(..Subcondities)
+]]></Implementation>
+</Method>
+
+<Method name="VoegToeKind">
+<FormalSpec>Kindknoop:TECH.Algo.Boom.Knoop</FormalSpec>
+<Implementation><![CDATA[	Do ..Subcondities.Insert(Kindknoop)
+]]></Implementation>
+</Method>
+</Class>
+</Export>
Index: TECH/Algo/SQL/QueryEngine/enu/CombinatieConditieOperator.cls.xml
===================================================================
diff -u
--- TECH/Algo/SQL/QueryEngine/enu/CombinatieConditieOperator.cls.xml	(revision 0)
+++ TECH/Algo/SQL/QueryEngine/enu/CombinatieConditieOperator.cls.xml	(revision 3044)
@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Export generator="Cache" version="9">
+<Class name="TECH.Algo.SQL.QueryEngine.enu.CombinatieConditieOperator">
+<ClassType>datatype</ClassType>
+<ProcedureBlock>1</ProcedureBlock>
+<Super>%String</Super>
+<ClassDefinitionError>0</ClassDefinitionError>
+
+<Parameter name="VALUELIST">
+<Default>;AND;OR</Default>
+</Parameter>
+
+<Method name="En">
+<ClassMethod>1</ClassMethod>
+<ReturnType>TECH.Algo.SQL.QueryEngine.enu.CombinatieConditieOperator</ReturnType>
+<Implementation><![CDATA[	Quit "AND"
+]]></Implementation>
+</Method>
+
+<Method name="Of">
+<ClassMethod>1</ClassMethod>
+<ReturnType>TECH.Algo.SQL.QueryEngine.enu.CombinatieConditieOperator</ReturnType>
+<Implementation><![CDATA[	Quit "OR"
+]]></Implementation>
+</Method>
+</Class>
+</Export>
Index: TECH/Algo/SQL/QueryEngine/QueryBuilder.cls.xml
===================================================================
diff -u -r3020 -r3044
--- TECH/Algo/SQL/QueryEngine/QueryBuilder.cls.xml	(.../QueryBuilder.cls.xml)	(revision 3020)
+++ TECH/Algo/SQL/QueryEngine/QueryBuilder.cls.xml	(.../QueryBuilder.cls.xml)	(revision 3044)
@@ -7,7 +7,7 @@
 
 <Property name="Tabellen">
 <Type>TECH.Algo.SQL.QueryEngine.Tabel</Type>
-<Collection>list</Collection>
+<Collection>array</Collection>
 <Private>1</Private>
 </Property>
 
@@ -23,13 +23,18 @@
 <Private>1</Private>
 </Property>
 
+<Property name="WhereConditie">
+<Type>TECH.Algo.SQL.QueryEngine.IWhereConditie</Type>
+<Private>1</Private>
+</Property>
+
 <Method name="VoegToeTabel">
 <FormalSpec>Tabel:TECH.Algo.SQL.QueryEngine.Tabel</FormalSpec>
-<Implementation><![CDATA[	Do ..Tabellen.Insert(Tabel)
+<Implementation><![CDATA[	Do ..Tabellen.SetAt(Tabel,Tabel.GeefNaam())
 ]]></Implementation>
 </Method>
 
-<Method name="GeefTabellenIterator">
+<Method name="GeefTabelIterator">
 <ReturnType>TECH.ListIterator</ReturnType>
 <Implementation><![CDATA[	Quit ##class(TECH.ListIterator).%New(..Tabellen)
 ]]></Implementation>
@@ -43,56 +48,83 @@
 
 <Method name="VoegToeForeignKey">
 <FormalSpec>ForeignKey:TECH.Algo.SQL.QueryEngine.ForeignKey</FormalSpec>
+<Implementation><![CDATA[	Do ..MapForeignKeyOpTabel(ForeignKey, ForeignKey.GeefTabel1())
+]]></Implementation>
+</Method>
+
+<Method name="MapForeignKeyOpTabel">
+<FormalSpec>ForeignKey:TECH.Algo.SQL.QueryEngine.ForeignKey,Tabel:TECH.Algo.SQL.QueryEngine.Tabel</FormalSpec>
+<Private>1</Private>
 <Implementation><![CDATA[
-	Set TabelNaam1 = ForeignKey.GeefTabel1().GeefNaam()
-	If ('..ForeignKeys.IsDefined(TabelNaam1)) { Do ..ForeignKeys.SetAt(##class(%ListOfObjects).%New(),TabelNaam1) }
-	Do ..ForeignKeys.GetAt(TabelNaam1).Insert(ForeignKey)
-	
-	Set TabelNaam2 = ForeignKey.GeefTabel2().GeefNaam()
-	If ('..ForeignKeys.IsDefined(TabelNaam2)) { Do ..ForeignKeys.SetAt(##class(%ListOfObjects).%New(),TabelNaam2) }
-	Do ..ForeignKeys.GetAt(TabelNaam2).Insert(ForeignKey)
+	Set TabelNaam = Tabel.GeefNaam()
+	If ('..ForeignKeys.IsDefined(TabelNaam)) { Do ..ForeignKeys.SetAt(##class(%ListOfObjects).%New(),TabelNaam) }
+	Do ..ForeignKeys.GetAt(TabelNaam).Insert(ForeignKey)
 ]]></Implementation>
 </Method>
 
+<Method name="ZetWhereConditie">
+<FormalSpec>WhereConditie:TECH.Algo.SQL.QueryEngine.IWhereConditie</FormalSpec>
+<Implementation><![CDATA[	Set ..WhereConditie = WhereConditie
+]]></Implementation>
+</Method>
+
 <Method name="GeefQueryString">
 <ReturnType>%String</ReturnType>
 <Implementation><![CDATA[
+	Set TabellenIterator = ##class(TECH.ListIterator).%New(..Tabellen)
+	
 	Set Query = "SELECT"
+	Set Query = Query_..GeefTeSelecterenVeldenString()
+	If (TabellenIterator.HasNext()) Set Query = Query_" "_..GeefFromTabelString(TabellenIterator.Next())
+	While (TabellenIterator.HasNext()) { Set Query = Query_" "_..GeefJoinTabelString(TabellenIterator.Next()) }
+	If ($IsObject(..WhereConditie)) Set Query = Query_" WHERE "_..WhereConditie.MaakConditieString()
 	
+	Quit Query
+]]></Implementation>
+</Method>
+
+<Method name="GeefTeSelecterenVeldenString">
+<Private>1</Private>
+<ReturnType>%String</ReturnType>
+<Implementation><![CDATA[
+	Set SelectieVeldString = ""
 	Set SelectieVeldenIterator = ##class(TECH.ListIterator).%New(..SelectieVelden)
 	While (SelectieVeldenIterator.HasNext())
 	{
 		Set SelectieVeld = SelectieVeldenIterator.Next()
-		Set Query = Query_" "_SelectieVeld.GeefTabel().GeefNaam()_"."_SelectieVeld.GeefVeld()
-		If (SelectieVeldenIterator.HasNext()) Set Query = Query_","
+		Set SelectieVeldString = SelectieVeldString_" "_SelectieVeld.GeefTabel().GeefNaam()_"."_SelectieVeld.GeefVeld()
+		If (SelectieVeldenIterator.HasNext()) Set SelectieVeldString = SelectieVeldString_","
 	}
-	
-	Set From = ""
-	Set TabellenIterator = ##class(TECH.ListIterator).%New(..Tabellen)
-	If (TabellenIterator.HasNext())
+	Quit SelectieVeldString
+]]></Implementation>
+</Method>
+
+<Method name="GeefFromTabelString">
+<FormalSpec>Tabel:TECH.Algo.SQL.QueryEngine.Tabel</FormalSpec>
+<Private>1</Private>
+<ReturnType>%String</ReturnType>
+<Implementation><![CDATA[	Quit "FROM "_Tabel.GeefNaam()
+]]></Implementation>
+</Method>
+
+<Method name="GeefJoinTabelString">
+<FormalSpec>Tabel:TECH.Algo.SQL.QueryEngine.Tabel</FormalSpec>
+<Private>1</Private>
+<ReturnType>%String</ReturnType>
+<Implementation><![CDATA[
+	Set JoinString = "JOIN "_Tabel.GeefNaam()
+	If (..ForeignKeys.IsDefined(Tabel.GeefNaam()))
 	{
-		Set From = "FROM "_ TabellenIterator.Next().GeefNaam()
-	}
-	
-	Set Joins = ""
-	While (TabellenIterator.HasNext())
-	{
-		Set Tabel = TabellenIterator.Next()
-		Set Joins = Joins_" JOIN "_Tabel.GeefNaam()
 		Set ForeignKeyIterator = ##class(TECH.ListIterator).%New(..ForeignKeys.GetAt(Tabel.GeefNaam()))
-		If (ForeignKeyIterator.HasNext()) Set Joins = Joins_" ON"
+		If (ForeignKeyIterator.HasNext()) Set JoinString = JoinString_" ON"
 		While (ForeignKeyIterator.HasNext())
 		{
 			Set ForeignKey = ForeignKeyIterator.Next()
-			Set Joins = Joins_" "_ForeignKey.GeefTabel1().GeefNaam()_"."_ForeignKey.GeefVeld1()_" = "_ForeignKey.GeefTabel2().GeefNaam()_"."_ForeignKey.GeefVeld2()
-			If (ForeignKeyIterator.HasNext()) { Set Joins = Joins_" AND" }
+			Set JoinString = JoinString_" "_ForeignKey.GeefTabel1().GeefNaam()_"."_ForeignKey.GeefVeld1()_" = "_ForeignKey.GeefTabel2().GeefNaam()_"."_ForeignKey.GeefVeld2()
+			If (ForeignKeyIterator.HasNext()) { Set JoinString = JoinString_" AND" }
 		}
 	}
-	
-	If ($Length(Joins) > 0) { Set Query = Query_Joins }
-	Set Query = Query_" "_From
-	
-	Quit Query
+	Quit JoinString
 ]]></Implementation>
 </Method>
 </Class>
Index: TECH/Algo/SQL/QueryEngine/IWhereConditie.cls.xml
===================================================================
diff -u
--- TECH/Algo/SQL/QueryEngine/IWhereConditie.cls.xml	(revision 0)
+++ TECH/Algo/SQL/QueryEngine/IWhereConditie.cls.xml	(revision 3044)
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Export generator="Cache" version="9">
+<Class name="TECH.Algo.SQL.QueryEngine.IWhereConditie">
+<Abstract>1</Abstract>
+<ProcedureBlock>1</ProcedureBlock>
+<Super>TECH.Algo.Boom.Knoop</Super>
+<ClassDefinitionError>0</ClassDefinitionError>
+
+<Method name="MaakConditieString">
+<Abstract>1</Abstract>
+<ReturnType>%String</ReturnType>
+</Method>
+</Class>
+</Export>