That happens because sometimes it is necessary to drop and recreate a table in order to change something. This can take a while, since all data must be copied to a temp table and then re-inserted in the new table. Since SQL Server by default doesn't trust you, you need to say "OK, I know what I'm doing, now let me do my work." This problem occurs when the Prevent saving changes that require the table re-creation option is enabled, and you make one or more of the following changes to the table:

• You change the Allow Nulls setting for a column.
• You reorder columns in the table.
• You change the column data type.
• You add a new column.

When you change a table so that you alter the metadata structure of the table, and then you save the table, the table must be re-created based on these changes. This may result in the loss of metadata and in a direct loss of data during the re-creation of the table. If you enable the Prevent saving changes that require the table re-creation option in the Designer section of the SQL Server Management Studio (SSMS) Options window, you receive the error message that is mentioned in the “Symptoms” section.

To change the Prevent saving changes that require the table re-creation option, follow these steps:

• Open SQL Server Management Studio (SSMS).
• On the Tools menu, click Options.
• In the navigation pane of the Options window, click Designers.
• Select or clear the Prevent saving changes that require the table re-creation check box, and then click OK.

Note If you disable this option, you are not warned when you save the table that the changes that you made have changed the metadata structure of the table. In this case, data loss may occur when you save the table.

Risk of turning off the “Prevent saving changes that require table re-creation” option

Although turning off this option can help you avoid re-creating a table, it can also lead to changes being lost. For example, suppose that you enable the Change Tracking feature in SQL Server to track changes to the table. When you perform an operation that causes the table to be re-created, you receive the error message that is mentioned in the “Symptoms” section. However, if you turn off this option, the existing change tracking information is deleted when the table is re-created. Therefore, we recommend that you do not work around this problem by turning off the option.

To determine whether the Change Tracking feature is enabled for a table, follow these steps:

• In SQL Server Management Studio, locate the table in Object Explorer.
• Right-click the table, and then click Properties.
• In the Table Properties dialog box, click Change Tracking.

If the value of the Change Tracking item is True, this option is enabled for the table. If the value is False, this option is disabled.

When the Change Tracking feature is enabled, use Transact-SQL statements to change the metadata structure of the table.

Steps to reproduce the problem

• In SQL Server Management Studio, create a table that contains a primary key in the Table Designer tool.
• Right-click the database that contains this table, and then click Properties.
• In the Database Properties dialog box, click Change Tracking.
• Set the value of the Change Tracking item to True, and then click OK.
• Right-click the table, and then click Properties.
• In the Table Properties dialog box, click Change Tracking.
• Set the value of the Change Tracking item to True, and then click OK.
• On the Tools menu, click Options.
• In the Options dialog box, click Designers.
• Click to select the Prevent saving changes that require table re-creation check box, and then click OK.
• In the Table Designer tool, change the Allow Nulls setting on an existing column.
• Try to save the change to the table.

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