When deleting a sheet in Excel, the system prompts: "This isam does not support deleting data in a chain table"

The original Excel file does not support deletion. The error "This isam does not support data deletion in the chain table" is returned when you delete from sheet1 $ ".
Because the rows in an Excel worksheet are somewhat different from those in a real relational database, if you use programming to access the data in an Excel worksheet, you can retrieve, insert, and update the data, however, if it is deleted, there will be some restrictions.
When deleting Excel data, there are more restrictions than when deleting data from a relational data source. In a relational database, "rows" have no meaning except a "record", but they are different in an Excel worksheet. You can delete values in fields (cells) but cannot:
1. delete a whole record at a time. Otherwise, the following error message will appear:
Deleting data in a linked table is not supported by this isam.
Only one record can be deleted by clearing the content of each field separately.
2. Delete the value in the cell containing the Excel Formula. Otherwise, the following error message is displayed:
Operation is not allowed in this context.
3. Although the original row of deleted data in the workbook is empty, it cannot be deleted, and the record set will continue to display empty records corresponding to these empty rows.
To solve this problem, the common simple method is to clear the field value, similar to the following statement:
Update sheet1 $ set name = NULL, deptname = NULL where deptid = 1;
Of course, what you need to know is that this row is not actually deleted, so we usually need to perform certain filtering during select, for example:
Select * From sheet1 $ where deptid is not null;