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Toad Data Point 6.2.3 - User Guide

Troubleshoot Excel® Issues

Review the following to help troubleshoot and solve issues involving Excel files.

See Create Excel Connections for more information about Excel connections.

Excel Connections

Issue

Cause/Solution

Tables are limited to 256 columns and 65536 rows.

This is a known limitation with Excel worksheets.

Column names longer than 64 characters are truncated and the remaining characters display as null.

This is a known limitation with Excel worksheets.

Columns that include text values or special characters as part of a numeric value, as well as entries with straight numeric values, result in one of the value sets displaying as null.

When you connect to Excel, the driver automatically scans the first eight rows in a column and applies the data type used in a majority of those rows to all rows in the column. Any rows that do not meet the majority data type display as null values.

Solution 1: Reformat worksheet column and values as text.

  1. Open the worksheet in Excel.

  2. Format the column that contains mixed data types as Text.

  3. You can now connect to this spreadsheet from Toad without any null values displayed.

Solution 2: Create an ODBC connection.

You can force the ODBC driver to read all rows as Text to avoid null values; however, this can result in issues if you attempt to insert data.

  1. Open the Create New Connection window and select ODBC from the Group list.

  2. Complete the fields as described in Create ODBC Connections.

  3. Enter "IMEX=1", in quotations, in the ExtraParameters field.

  4. Click Connect.

Column names that contain an exclamation point (!) are not supported.

The exclamation point character has a special meaning in Excel. If a column name contains an exclamation point, it is internally converted to a dollar sign ($) character.

Tables cannot be altered.

Tables cannot be altered when the Excel connection is Read-Only.

Solution: Deselect Read-Only Connection in the Connection Properties dialog.

The Primary Keys and Foreign Keys tabs are blank in the Database Explorer.

Excel is a spreadsheet, and does not support primary and foreign keys so these tabs are always blank.

Indexes cannot be created or dropped.

The Excel ODBC driver does not support this functionality.

Unable to query Excel files without named ranges (regions).

The worksheet you are querying does not have named ranges (regions) defined.

Solution:

You can query the worksheet from the Editor by entering a dollar sign ($) followed by a cell range to limit the results similar to the following statement: 

Select * from (MyWorksheet$A1:C10)

You can also query the entire worksheet by entering a dollar sign ($) after the worksheet name. However, this may also return the worksheet's empty rows and columns.

Attempting to connect to or create a new Excel connection results in No user tables could be found message.

The Excel file does not have named ranges (regions) defined. If you click OK to close the message, the new connection is created, but no user tables display in Object Explorer. (System tables are displayed, if you selected to show these.)

Solution 1: In the Excel file, create named ranges.

Solution 2: Ask Toad to automatically create named ranges.

  1. Disconnect from the file.
  2. In Navigation Manager, right-click the file and select Properties | Advanced.
  3. Select Automatically create ranges.

    The next time you connect, Toad automatically creates named ranges, which are then displayed as tables.

See Create Excel Connections for more information.

Unable to query data using an empty string or null value.

The underlying data format cannot differentiate between an empty string and null data, so a query with a search condition that contains an empty string does not match any empty strings in the table. This occurs because the empty string is treated as a null value, and a null value never matches anything, not even another null value.

Unable to update or delete rows in a table.

The Excel ODBC driver does not support this functionality. While it is possible to update values, DELETE statements do not remove a row from a table. Basically, you can only insert data in a table.

Attempting to insert data results in Cannot expand named range error.

This error occurs if you have more than one named range (region) in the same worksheet, and the named ranges are not separated by blank rows.

Solution 1: You must add blank rows between named ranges. Add as many blank rows as you have new records to insert.

Solution 2: Include only one named range in each worksheet.

Working with Excel Files

Issue

Cause/Solution

Microsoft Excel worksheet row and column limits

When exporting to Excel, be aware that Excel worksheets have limits for maximum number of rows and columns supported.

See Microsoft Excel specifications and limits for more information.

Opening Excel Files in Toad Document Window

Issue Cause/Solution

Excel menus do not display when you open Excel files in a Toad document window.

The Toad document window cannot display all Excel menus.

Solution:

Right-click the Excel toolbar and add the equivalent toolbar for the missing menu or functionality.

When two or more instances of Excel are open in Toad document windows, toolbars are active for only one instance.

Toad document windows support one Excel instance at a time. Opening more than one Excel file disables the Excel toolbars for the additional files.

Solution:

Open only one Excel file at a time.

 

Related Topics

Open Excel® Files

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