Rename rows to columns and omit empty indices

d2compiler/compile.go

@@ -680,11 +680,12 @@ func (c *compiler) compileSQLTable(obj *d2graph.Object) {
 				continue
 			}
 			if srcID == absID {
-				// Frontend isn't aware of container IDs.
 				d2Col.Reference = strings.TrimPrefix(dstID, parentID+".")
-				e.FromTableRowIndex = len(obj.SQLTable.Columns)
-			} else {
-				e.ToTableRowIndex = len(obj.SQLTable.Columns)
+				e.FromTableColumnIndex = new(int)
+				*e.FromTableColumnIndex = len(obj.SQLTable.Columns)
+			} else if dstID == absID {
+				e.ToTableColumnIndex = new(int)
+				*e.ToTableColumnIndex = len(obj.SQLTable.Columns)
 			}
 		}
 
@@ -745,8 +746,10 @@ func flattenContainer(g *d2graph.Graph, obj *d2graph.Object) {
 			newEdge, _ = g.Root.Connect(e.Src.AbsIDArray(), obj.AbsIDArray(), e.SrcArrow, e.DstArrow, e.Attributes.Label.Value)
 		}
 		// TODO more attributes
-		newEdge.FromTableRowIndex = e.FromTableRowIndex
-		newEdge.ToTableRowIndex = e.ToTableRowIndex
+		newEdge.FromTableColumnIndex = new(int)
+		*newEdge.FromTableColumnIndex = *e.FromTableColumnIndex
+		newEdge.ToTableColumnIndex = new(int)
+		*newEdge.ToTableColumnIndex = *e.ToTableColumnIndex
 		newEdge.Attributes.Label = e.Attributes.Label
 		newEdge.References = e.References
 	}

d2graph/d2graph.go

@@ -607,8 +607,8 @@ type Edge struct {
 	MinWidth  int `json:"minWidth"`
 	MinHeight int `json:"minHeight"`
 
-	FromTableRowIndex int `json:"fromTableRowIndex"`
-	ToTableRowIndex   int `json:"toTableRowIndex"`
+	FromTableColumnIndex *int `json:"fromTableColumnIndex,omitempty"`
+	ToTableColumnIndex   *int `json:"toTableColumnIndex,omitempty"`
 
 	LabelDimensions d2target.TextDimensions `json:"label_dimensions"`
 	LabelPosition   *string                 `json:"labelPosition,omitempty"`

e2etests/stable_test.go

@@ -831,6 +831,44 @@ a -> md -> b
   +setTimeout(seconds int)
 }
 `,
+		}, {
+			name: "sql_tables",
+			script: `
+			users: {
+			  shape: sql_table
+			  id: int
+			  name: string
+			  email: string
+			  password: string
+			  last_login: datetime
+			}
+
+			products: {
+			  shape: sql_table
+			  id: int
+			  price: decimal
+			  sku: string
+			  name: string
+			}
+
+			orders: {
+			  shape: sql_table
+			  id: int
+			  user_id: int
+			  product_id: int
+			}
+
+			shipments: {
+			  shape: sql_table
+			  id: int
+			  order_id: int
+			  tracking_number: string
+			  status: string
+			}
+
+			users.id <-> orders.user_id
+			products.id <-> orders.product_id
+			shipments.order_id <-> orders.id`,
 		},
 	}