Added diff to the tool

pkg/readers/dbml/reader.go

@@ -344,11 +344,12 @@ func (r *Reader) parseIndex(line, tableName, schemaName string) *models.Index {
 		for _, col := range strings.Split(columnsStr, ",") {
 			columns = append(columns, stripQuotes(strings.TrimSpace(col)))
 		}
-	} else {
+	} else if strings.Contains(line, "[") {
 		// Single column format: columnname [attributes]
 		// Extract column name before the bracket
-		if strings.Contains(line, "[") {
-			colName := strings.TrimSpace(line[:strings.Index(line, "[")])
+		idx := strings.Index(line, "[")
+		if idx > 0 {
+			colName := strings.TrimSpace(line[:idx])
 			if colName != "" {
 				columns = []string{stripQuotes(colName)}
 			}