SharePoint 2010 Data loss after column data type changed

Question

Hi,

Currently we are doing one migration assignment. From Lotus Notes we migrated arround 10000 items to a
SharePoint list. After migration we converted one single line text field to multiple lines of text.
And suddenly all the data associated with that field got lost.

Can anyone please suggest remeady to get out of this??

Many Thnaks,

Pratima

Answer 1

In order to maintain the data, I believe instead of changing the data type on that column that you will need to create a new column which is set to multiple lines of text. Copy the data from the old column to the new column and then delete the old column.

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JD Wade
Senior SharePoint Consultant, MCTS
Horizons Consulting, Inc.
Blog: http://wadingthrough.com
Twitter: http://twitter.com/jdwade

Answer 2

Hello JD Wade

I have got the cause behind above problem and got the solution too.

When we change data type of single line text column to multiline, new version of all items is created. In which all other columns' values get retained. But the column for which data type is changed to multiline, get overwritten with empty multiline field. If versioning is set off for corresponding list, the latest version with empty multiline field will be overwritten on existing record. And so all the data will be lost.

When you want to change data type of any column to some equivalent data type without loosing data and without creating additional versions, the best solution is:

1. Open List Settings
2. Open Versioning Settings under General Settings
3. In section Item Version History, select Yes for Create a version each time you edit an item in this list
4. Check the option Optionally limit the number of versions to retain
5. Set the Keep the following number of versions option to 1
6. Now go to column for which data type has to be changed. Change the column type in section Type and Name
7. In section Additional Column Settings, select Yes for Append Changes to Existing Text option.

This will change the column data type, as well as retain the old value of respective column(Append changes to Existing Text is set to Yes). As we have set number of versions to 1, it will also not create additional versions.

Cheers,

Pratima