Warning against 1:n joins in form editor

www/comps/builder/builderForm.css

@@ -44,6 +44,30 @@
 	text-decoration-thickness:4px;
 }
 
+.builder-form .sidebar .warning{
+	margin:6px;
+	display:flex;
+	flex-flow:row nowrap;
+	align-items:center;
+	gap:6px;
+	cursor:pointer;
+}
+.builder-form .sidebar .warning>img{
+	width:24px;
+	margin:2px;
+	filter:var(--image-filter-error);
+}
+.builder-form .sidebar .warning>span{
+	color:var(--color-error);
+}
+.builder-form .sidebar .warning:hover>img{
+	width:28px;
+	margin:0px;
+}
+.builder-form .sidebar .warning:hover>span{
+	text-decoration:underline;
+}
+
 /* form builder main area */
 .builder-form-main{
 	flex:2 1 auto;

www/comps/builder/builderForm.js

@@ -222,6 +222,14 @@ let MyBuilderForm = {
 						:relationId="relationId"
 					/>
 					
+					<!-- 1:n join warning -->
+					<div v-if="tabTarget === 'content' && hasAny1nJoin" class="warning"
+						@click="showMessage(capApp.warning.joinN1,capApp.warning.joinN1Hint,'link2.png')"
+					>
+						<img src="images/link2.png" />
+						<span>{{ capApp.warning.joinN1Hint }}</span>
+					</div>
+					
 					<!-- template fields -->
 					<div class="templates-wrap" v-if="tabTarget === 'content'">
 						<h2>{{ capApp.fields }}</h2>
@@ -677,6 +685,19 @@ let MyBuilderForm = {
 
 			return atr.relationId;
 		},
+		hasAny1nJoin:(s) => {
+			for(let j of s.joins) {
+				if(j.index === 0)
+					continue;
+
+				let joinAtr = s.attributeIdMap[j.attributeId];
+
+				// join via 1:n attribute (outside-in join)
+				if(s.isAttributeRelationshipN1(joinAtr.content) && joinAtr.relationId === j.relationId)
+					return true;
+			}
+			return false;
+		},
 
 		// simple
 		columnShow:       (s) => s.columnIdShow === null ? false : s.columnIdMap[s.columnIdShow],
@@ -741,9 +762,11 @@ let MyBuilderForm = {
 			this.fieldMoveList  = evt.fieldList;
 			this.fieldMoveIndex = evt.fieldIndex;
 		},
-		showMessage(msg) {
+		showMessage(msg,top,image) {
 			this.$store.commit('dialog',{
+				captionTop:top,
 				captionBody:msg,
+				image:image,
 				buttons:[{
 					caption:this.capGen.button.close,
 					cancel:true,

www/langs/REPLACE_BY_BUILD/de_de

@@ -824,6 +824,8 @@
 			"warning":{
 				"calendarNoDateFromTo":"Kein Attribut ausgewählt für \"Datum von\" oder \"Datum zu\". Beide sind notwendig, damit ein Kalenderfeld arbeiten kann.",
 				"columnNoSubQueryAttribute":"Keine Relation & Attribut ausgewählt für eine Sub-Query-Spalte.",
+				"joinN1":"Relationen zu verbinden dient der gleichzeitigen Bearbeitung mehrerer, assoziierter Datensätze. Ein Formular kann aber immer nur einen Datensatz je Relation verarbeiten.<br /><br />Wenn eine 1:n-Beziehung zur Verbindung genutzt wird, können mehrere Datensätze für eine Relation existieren. Falls dies geschieht, zeigt das Formular einen Fehler.<br /><br />1:n-Beziehungen zu verwenden ist valide, solange der Formularinhalt so gefiltert wird, dass jede Relation maximal 1 Datensatz haben kann.",
+				"joinN1Hint":"Warnung! 1:n-Verbindung im Formularinhalt erkannt",
 				"queryColumnsNotSet":"Keine angezeigten Spalten. Eine Spalte hinzufügen, um Daten anzuzeigen.",
 				"queryRelationNotSet":"Keine Relation ausgewählt. Feld hat keinen Zugriff auf Daten."
 			},

www/langs/REPLACE_BY_BUILD/en_us

@@ -824,6 +824,8 @@
 			"warning":{
 				"calendarNoDateFromTo":"No attribute selected for 'date from' or 'date to'. Both are required for a calendar field to work.",
 				"columnNoSubQueryAttribute":"No relation & attribute chosen for a sub query column.",
+				"joinN1":"Joining relations on a form serves to update multiple, connected records at the same time. However, a form can only handle a single record per relation.<br /><br />Using a 1:n relationship for a join can lead to multiple records being available on a single relation. If this happens, the form will show an error.<br /><br />Using 1:n relationships for joins is valid, if the form content is being filtered so that each relation can never have more than 1 record.",
+				"joinN1Hint":"Warning! 1:n join detected in form content",
 				"queryColumnsNotSet":"No displayed columns. Add any column to show data.",
 				"queryRelationNotSet":"No relation selected. Field has no access to data."
 			},

www/langs/REPLACE_BY_BUILD/it_it

@@ -824,6 +824,8 @@
 			"warning":{
 				"calendarNoDateFromTo":"No attribute selected for 'date from' or 'date to'. Both are required for a calendar field to work.",
 				"columnNoSubQueryAttribute":"No relation & attribute chosen for a sub query column.",
+				"joinN1":"Joining relations on a form serves to update multiple, connected records at the same time. However, a form can only handle a single record per relation.<br /><br />Using a 1:n relationship for a join can lead to multiple records being available on a single relation. If this happens, the form will show an error.<br /><br />Using 1:n relationships for joins is valid, if the form content is being filtered so that each relation can never have more than 1 record.",
+				"joinN1Hint":"Warning! 1:n join detected in form content",
 				"queryColumnsNotSet":"No displayed columns. Add any column to show data.",
 				"queryRelationNotSet":"No relation selected. Field has no access to data."
 			},

www/langs/REPLACE_BY_BUILD/ro_ro

@@ -824,6 +824,8 @@
 			"warning":{
 				"calendarNoDateFromTo":"No attribute selected for 'date from' or 'date to'. Both are required for a calendar field to work.",
 				"columnNoSubQueryAttribute":"No relation & attribute chosen for a sub query column.",
+				"joinN1":"Joining relations on a form serves to update multiple, connected records at the same time. However, a form can only handle a single record per relation.<br /><br />Using a 1:n relationship for a join can lead to multiple records being available on a single relation. If this happens, the form will show an error.<br /><br />Using 1:n relationships for joins is valid, if the form content is being filtered so that each relation can never have more than 1 record.",
+				"joinN1Hint":"Warning! 1:n join detected in form content",
 				"queryColumnsNotSet":"No displayed columns. Add any column to show data.",
 				"queryRelationNotSet":"No relation selected. Field has no access to data."
 			},