fix: fetch columns if required

Signed-off-by: mertmit <mertmit99@gmail.com>

packages/nocodb/src/db/BaseModelSqlv2.ts

@@ -4000,7 +4000,7 @@ class BaseModelSqlv2 {
         : await this.dbDriver.raw(query);
 
     // update attachment fields
-    data = this.convertAttachmentType(data, childTable);
+    data = await this.convertAttachmentType(data, childTable);
 
     // update date time fields
     data = this.convertDateFormat(data, childTable);
@@ -4024,7 +4024,16 @@ class BaseModelSqlv2 {
     return d;
   }
 
-  public convertAttachmentType(data: Record<string, any>, childTable?: Model) {
+  public async convertAttachmentType(
+    data: Record<string, any>,
+    childTable?: Model,
+  ) {
+    if (childTable && !childTable?.columns) {
+      await childTable.getColumns();
+    } else if (!this.model?.columns) {
+      await this.model.getColumns();
+    }
+
     // attachment is stored in text and parse in UI
     // convertAttachmentType is used to convert the response in string to array of object in API response
     if (data) {